diff --git a/packages/block-editor/src/store/reducer.js b/packages/block-editor/src/store/reducer.js
index d9d0ecbdd28b6..a2df297f3e136 100644
--- a/packages/block-editor/src/store/reducer.js
+++ b/packages/block-editor/src/store/reducer.js
@@ -54,6 +54,23 @@ function mapBlockOrder( blocks, rootClientId = '' ) {
 	return result;
 }
 
+/**
+ * Given an array of blocks, returns an object where each key contains
+ * the clientId of the block and the value is the parent of the block.
+ *
+ * @param {Array}   blocks       Blocks to map.
+ * @param {?string} rootClientId Assumed root client ID.
+ *
+ * @return {Object} Block order map object.
+ */
+function mapBlockParents( blocks, rootClientId = '' ) {
+	return blocks.reduce( ( result, block ) => Object.assign(
+		result,
+		{ [ block.clientId ]: rootClientId },
+		mapBlockParents( block.innerBlocks, block.clientId )
+	), {} );
+}
+
 /**
  * Helper method to iterate through all blocks, recursing into inner blocks,
  * applying a transformation function to each one.
@@ -264,16 +281,40 @@ function withIgnoredBlockChange( reducer ) {
  * @return {Function} Enhanced reducer function.
  */
 const withInnerBlocksRemoveCascade = ( reducer ) => ( state, action ) => {
-	if ( state && action.type === 'REMOVE_BLOCKS' ) {
-		const clientIds = [ ...action.clientIds ];
+	const getAllChildren = ( clientIds ) => {
+		let result = clientIds;
+		for ( let i = 0; i < result.length; i++ ) {
+			if ( ! state.order[ result[ i ] ] ) {
+				continue;
+			}
 
-		// For each removed client ID, include its inner blocks to remove,
-		// recursing into those so long as inner blocks exist.
-		for ( let i = 0; i < clientIds.length; i++ ) {
-			clientIds.push( ...state.order[ clientIds[ i ] ] );
+			if ( result === clientIds ) {
+				result = [ ...result ];
+			}
+
+			result.push( ...state.order[ result[ i ] ] );
 		}
 
-		action = { ...action, clientIds };
+		return result;
+	};
+
+	if ( state ) {
+		switch ( action.type ) {
+			case 'REMOVE_BLOCKS':
+				action = {
+					...action,
+					type: 'REMOVE_BLOCKS_AUGMENTED_WITH_CHILDREN',
+					removedClientIds: getAllChildren( action.clientIds ),
+				};
+				break;
+			case 'REPLACE_BLOCKS':
+				action = {
+					...action,
+					type: 'REPLACE_BLOCKS_AUGMENTED_WITH_CHILDREN',
+					replacedClientIds: getAllChildren( action.clientIds ),
+				};
+				break;
+		}
 	}
 
 	return reducer( state, action );
@@ -306,6 +347,10 @@ const withBlockReset = ( reducer ) => ( state, action ) => {
 				...omit( state.order, visibleClientIds ),
 				...mapBlockOrder( action.blocks ),
 			},
+			parents: {
+				...omit( state.parents, visibleClientIds ),
+				...mapBlockParents( action.blocks ),
+			},
 		};
 	}
 
@@ -435,18 +480,18 @@ export const blocks = flow(
 					...getFlattenedBlocksWithoutAttributes( action.blocks ),
 				};
 
-			case 'REPLACE_BLOCKS':
+			case 'REPLACE_BLOCKS_AUGMENTED_WITH_CHILDREN':
 				if ( ! action.blocks ) {
 					return state;
 				}
 
 				return {
-					...omit( state, action.clientIds ),
+					...omit( state, action.replacedClientIds ),
 					...getFlattenedBlocksWithoutAttributes( action.blocks ),
 				};
 
-			case 'REMOVE_BLOCKS':
-				return omit( state, action.clientIds );
+			case 'REMOVE_BLOCKS_AUGMENTED_WITH_CHILDREN':
+				return omit( state, action.removedClientIds );
 		}
 
 		return state;
@@ -511,18 +556,18 @@ export const blocks = flow(
 					...getFlattenedBlockAttributes( action.blocks ),
 				};
 
-			case 'REPLACE_BLOCKS':
+			case 'REPLACE_BLOCKS_AUGMENTED_WITH_CHILDREN':
 				if ( ! action.blocks ) {
 					return state;
 				}
 
 				return {
-					...omit( state, action.clientIds ),
+					...omit( state, action.replacedClientIds ),
 					...getFlattenedBlockAttributes( action.blocks ),
 				};
 
-			case 'REMOVE_BLOCKS':
-				return omit( state, action.clientIds );
+			case 'REMOVE_BLOCKS_AUGMENTED_WITH_CHILDREN':
+				return omit( state, action.removedClientIds );
 		}
 
 		return state;
@@ -609,7 +654,7 @@ export const blocks = flow(
 				};
 			}
 
-			case 'REPLACE_BLOCKS': {
+			case 'REPLACE_BLOCKS_AUGMENTED_WITH_CHILDREN': {
 				const { clientIds } = action;
 				if ( ! action.blocks ) {
 					return state;
@@ -618,7 +663,7 @@ export const blocks = flow(
 				const mappedBlocks = mapBlockOrder( action.blocks );
 
 				return flow( [
-					( nextState ) => omit( nextState, clientIds ),
+					( nextState ) => omit( nextState, action.replacedClientIds ),
 					( nextState ) => ( {
 						...nextState,
 						...omit( mappedBlocks, '' ),
@@ -642,20 +687,59 @@ export const blocks = flow(
 				] )( state );
 			}
 
-			case 'REMOVE_BLOCKS':
+			case 'REMOVE_BLOCKS_AUGMENTED_WITH_CHILDREN':
 				return flow( [
 					// Remove inner block ordering for removed blocks
-					( nextState ) => omit( nextState, action.clientIds ),
+					( nextState ) => omit( nextState, action.removedClientIds ),
 
 					// Remove deleted blocks from other blocks' orderings
 					( nextState ) => mapValues( nextState, ( subState ) => (
-						without( subState, ...action.clientIds )
+						without( subState, ...action.removedClientIds )
 					) ),
 				] )( state );
 		}
 
 		return state;
 	},
+
+	// While technically redundant data as the inverse of `order`, it serves as
+	// an optimization for the selectors which derive the ancestry of a block.
+	parents( state = {}, action ) {
+		switch ( action.type ) {
+			case 'RESET_BLOCKS':
+				return mapBlockParents( action.blocks );
+
+			case 'RECEIVE_BLOCKS':
+				return {
+					...state,
+					...mapBlockParents( action.blocks ),
+				};
+
+			case 'INSERT_BLOCKS':
+				return {
+					...state,
+					...mapBlockParents( action.blocks, action.rootClientId || '' ),
+				};
+
+			case 'MOVE_BLOCK_TO_POSITION': {
+				return {
+					...state,
+					[ action.clientId ]: action.toRootClientId || '',
+				};
+			}
+
+			case 'REPLACE_BLOCKS_AUGMENTED_WITH_CHILDREN':
+				return {
+					...omit( state, action.replacedClientIds ),
+					...mapBlockParents( action.blocks, state[ action.clientIds[ 0 ] ] ),
+				};
+
+			case 'REMOVE_BLOCKS_AUGMENTED_WITH_CHILDREN':
+				return omit( state, action.removedClientIds );
+		}
+
+		return state;
+	},
 } );
 
 /**
diff --git a/packages/block-editor/src/store/selectors.js b/packages/block-editor/src/store/selectors.js
index 6633611fbd9b1..21937e3bc3d8a 100644
--- a/packages/block-editor/src/store/selectors.js
+++ b/packages/block-editor/src/store/selectors.js
@@ -458,22 +458,11 @@ export function getSelectedBlock( state ) {
  *
  * @return {?string} Root client ID, if exists
  */
-export const getBlockRootClientId = createSelector(
-	( state, clientId ) => {
-		const { order } = state.blocks;
-
-		for ( const rootClientId in order ) {
-			if ( includes( order[ rootClientId ], clientId ) ) {
-				return rootClientId;
-			}
-		}
-
-		return null;
-	},
-	( state ) => [
-		state.blocks.order,
-	]
-);
+export function getBlockRootClientId( state, clientId ) {
+	return state.blocks.parents[ clientId ] !== undefined ?
+		state.blocks.parents[ clientId ] :
+		null;
+}
 
 /**
  * Given a block client ID, returns the root of the hierarchy from which the block is nested, return the block itself for root level blocks.
@@ -483,21 +472,15 @@ export const getBlockRootClientId = createSelector(
  *
  * @return {string} Root client ID
  */
-export const getBlockHierarchyRootClientId = createSelector(
-	( state, clientId ) => {
-		let rootClientId = clientId;
-		let current = clientId;
-		while ( rootClientId ) {
-			current = rootClientId;
-			rootClientId = getBlockRootClientId( state, current );
-		}
-
-		return current;
-	},
-	( state ) => [
-		state.blocks.order,
-	]
-);
+export function getBlockHierarchyRootClientId( state, clientId ) {
+	let current = clientId;
+	let parent;
+	do {
+		parent = current;
+		current = state.blocks.parents[ current ];
+	} while ( current );
+	return parent;
+}
 
 /**
  * Returns the client ID of the block adjacent one at the given reference
diff --git a/packages/block-editor/src/store/test/reducer.js b/packages/block-editor/src/store/test/reducer.js
index 7543fdad57dd8..90116e7805254 100644
--- a/packages/block-editor/src/store/test/reducer.js
+++ b/packages/block-editor/src/store/test/reducer.js
@@ -193,27 +193,31 @@ describe( 'state', () => {
 			it( 'can replace a child block', () => {
 				const existingState = deepFreeze( {
 					byClientId: {
-						clicken: {
+						chicken: {
 							clientId: 'chicken',
 							name: 'core/test-parent-block',
 							isValid: true,
 						},
-						'clicken-child': {
+						'chicken-child': {
 							clientId: 'chicken-child',
 							name: 'core/test-child-block',
 							isValid: true,
 						},
 					},
 					attributes: {
-						clicken: {},
-						'clicken-child': {
+						chicken: {},
+						'chicken-child': {
 							attr: true,
 						},
 					},
 					order: {
-						'': [ 'clicken' ],
-						clicken: [ 'clicken-child' ],
-						'clicken-child': [],
+						'': [ 'chicken' ],
+						chicken: [ 'chicken-child' ],
+						'chicken-child': [],
+					},
+					parents: {
+						chicken: '',
+						'chicken-child': 'chicken',
 					},
 				} );
 
@@ -226,7 +230,7 @@ describe( 'state', () => {
 
 				const action = {
 					type: 'REPLACE_INNER_BLOCKS',
-					rootClientId: 'clicken',
+					rootClientId: 'chicken',
 					blocks: [ newChildBlock ],
 				};
 
@@ -236,7 +240,7 @@ describe( 'state', () => {
 					isPersistentChange: true,
 					isIgnoredChange: false,
 					byClientId: {
-						clicken: {
+						chicken: {
 							clientId: 'chicken',
 							name: 'core/test-parent-block',
 							isValid: true,
@@ -248,35 +252,42 @@ describe( 'state', () => {
 						},
 					},
 					attributes: {
-						clicken: {},
+						chicken: {},
 						[ newChildBlockId ]: {
 							attr: false,
 							attr2: 'perfect',
 						},
 					},
 					order: {
-						'': [ 'clicken' ],
-						clicken: [ newChildBlockId ],
+						'': [ 'chicken' ],
+						chicken: [ newChildBlockId ],
 						[ newChildBlockId ]: [],
 					},
+					parents: {
+						[ newChildBlockId ]: 'chicken',
+						chicken: '',
+					},
 				} );
 			} );
 
 			it( 'can insert a child block', () => {
 				const existingState = deepFreeze( {
 					byClientId: {
-						clicken: {
+						chicken: {
 							clientId: 'chicken',
 							name: 'core/test-parent-block',
 							isValid: true,
 						},
 					},
 					attributes: {
-						clicken: {},
+						chicken: {},
 					},
 					order: {
-						'': [ 'clicken' ],
-						clicken: [],
+						'': [ 'chicken' ],
+						chicken: [],
+					},
+					parents: {
+						chicken: '',
 					},
 				} );
 
@@ -289,7 +300,7 @@ describe( 'state', () => {
 
 				const action = {
 					type: 'REPLACE_INNER_BLOCKS',
-					rootClientId: 'clicken',
+					rootClientId: 'chicken',
 					blocks: [ newChildBlock ],
 				};
 
@@ -299,7 +310,7 @@ describe( 'state', () => {
 					isPersistentChange: true,
 					isIgnoredChange: false,
 					byClientId: {
-						clicken: {
+						chicken: {
 							clientId: 'chicken',
 							name: 'core/test-parent-block',
 							isValid: true,
@@ -311,53 +322,62 @@ describe( 'state', () => {
 						},
 					},
 					attributes: {
-						clicken: {},
+						chicken: {},
 						[ newChildBlockId ]: {
 							attr: false,
 							attr2: 'perfect',
 						},
 					},
 					order: {
-						'': [ 'clicken' ],
-						clicken: [ newChildBlockId ],
+						'': [ 'chicken' ],
+						chicken: [ newChildBlockId ],
 						[ newChildBlockId ]: [],
 					},
+					parents: {
+						[ newChildBlockId ]: 'chicken',
+						chicken: '',
+					},
 				} );
 			} );
 
 			it( 'can replace multiple child blocks', () => {
 				const existingState = deepFreeze( {
 					byClientId: {
-						clicken: {
+						chicken: {
 							clientId: 'chicken',
 							name: 'core/test-parent-block',
 							isValid: true,
 						},
-						'clicken-child': {
+						'chicken-child': {
 							clientId: 'chicken-child',
 							name: 'core/test-child-block',
 							isValid: true,
 						},
-						'clicken-child-2': {
+						'chicken-child-2': {
 							clientId: 'chicken-child',
 							name: 'core/test-child-block',
 							isValid: true,
 						},
 					},
 					attributes: {
-						clicken: {},
-						'clicken-child': {
+						chicken: {},
+						'chicken-child': {
 							attr: true,
 						},
-						'clicken-child-2': {
+						'chicken-child-2': {
 							attr2: 'ok',
 						},
 					},
 					order: {
-						'': [ 'clicken' ],
-						clicken: [ 'clicken-child', 'clicken-child-2' ],
-						'clicken-child': [],
-						'clicken-child-2': [],
+						'': [ 'chicken' ],
+						chicken: [ 'chicken-child', 'chicken-child-2' ],
+						'chicken-child': [],
+						'chicken-child-2': [],
+					},
+					parents: {
+						chicken: '',
+						'chicken-child': 'chicken',
+						'chicken-child-2': 'chicken',
 					},
 				} );
 
@@ -381,7 +401,7 @@ describe( 'state', () => {
 
 				const action = {
 					type: 'REPLACE_INNER_BLOCKS',
-					rootClientId: 'clicken',
+					rootClientId: 'chicken',
 					blocks: [ newChildBlock1, newChildBlock2, newChildBlock3 ],
 				};
 
@@ -391,7 +411,7 @@ describe( 'state', () => {
 					isPersistentChange: true,
 					isIgnoredChange: false,
 					byClientId: {
-						clicken: {
+						chicken: {
 							clientId: 'chicken',
 							name: 'core/test-parent-block',
 							isValid: true,
@@ -413,7 +433,7 @@ describe( 'state', () => {
 						},
 					},
 					attributes: {
-						clicken: {},
+						chicken: {},
 						[ newChildBlockId1 ]: {
 							attr: false,
 							attr2: 'perfect',
@@ -427,44 +447,55 @@ describe( 'state', () => {
 						},
 					},
 					order: {
-						'': [ 'clicken' ],
-						clicken: [ newChildBlockId1, newChildBlockId2, newChildBlockId3 ],
+						'': [ 'chicken' ],
+						chicken: [ newChildBlockId1, newChildBlockId2, newChildBlockId3 ],
 						[ newChildBlockId1 ]: [],
 						[ newChildBlockId2 ]: [],
 						[ newChildBlockId3 ]: [],
 					},
+					parents: {
+						chicken: '',
+						[ newChildBlockId1 ]: 'chicken',
+						[ newChildBlockId2 ]: 'chicken',
+						[ newChildBlockId3 ]: 'chicken',
+					},
 				} );
 			} );
 
 			it( 'can replace a child block that has other children', () => {
 				const existingState = deepFreeze( {
 					byClientId: {
-						clicken: {
+						chicken: {
 							clientId: 'chicken',
 							name: 'core/test-parent-block',
 							isValid: true,
 						},
-						'clicken-child': {
+						'chicken-child': {
 							clientId: 'chicken-child',
 							name: 'core/test-child-block',
 							isValid: true,
 						},
-						'clicken-grand-child': {
+						'chicken-grand-child': {
 							clientId: 'chicken-child',
 							name: 'core/test-block',
 							isValid: true,
 						},
 					},
 					attributes: {
-						clicken: {},
-						'clicken-child': {},
-						'clicken-grand-child': {},
+						chicken: {},
+						'chicken-child': {},
+						'chicken-grand-child': {},
 					},
 					order: {
-						'': [ 'clicken' ],
-						clicken: [ 'clicken-child' ],
-						'clicken-child': [ 'clicken-grand-child' ],
-						'clicken-grand-child': [],
+						'': [ 'chicken' ],
+						chicken: [ 'chicken-child' ],
+						'chicken-child': [ 'chicken-grand-child' ],
+						'chicken-grand-child': [],
+					},
+					parents: {
+						chicken: '',
+						'chicken-child': 'chicken',
+						'chicken-grand-child': 'chicken-child',
 					},
 				} );
 
@@ -474,7 +505,7 @@ describe( 'state', () => {
 
 				const action = {
 					type: 'REPLACE_INNER_BLOCKS',
-					rootClientId: 'clicken',
+					rootClientId: 'chicken',
 					blocks: [ newChildBlock ],
 				};
 
@@ -484,7 +515,7 @@ describe( 'state', () => {
 					isPersistentChange: true,
 					isIgnoredChange: false,
 					byClientId: {
-						clicken: {
+						chicken: {
 							clientId: 'chicken',
 							name: 'core/test-parent-block',
 							isValid: true,
@@ -496,14 +527,18 @@ describe( 'state', () => {
 						},
 					},
 					attributes: {
-						clicken: {},
+						chicken: {},
 						[ newChildBlockId ]: {},
 					},
 					order: {
-						'': [ 'clicken' ],
-						clicken: [ newChildBlockId ],
+						'': [ 'chicken' ],
+						chicken: [ newChildBlockId ],
 						[ newChildBlockId ]: [],
 					},
+					parents: {
+						chicken: '',
+						[ newChildBlockId ]: 'chicken',
+					},
 				} );
 			} );
 		} );
@@ -515,6 +550,7 @@ describe( 'state', () => {
 				byClientId: {},
 				attributes: {},
 				order: {},
+				parents: {},
 				isPersistentChange: true,
 				isIgnoredChange: false,
 			} );
@@ -612,6 +648,45 @@ describe( 'state', () => {
 				'': [ 'wings' ],
 				wings: [],
 			} );
+			expect( state.parents ).toEqual( {
+				wings: '',
+			} );
+		} );
+		it( 'should replace the block and remove references to its inner blocks', () => {
+			const original = blocks( undefined, {
+				type: 'RESET_BLOCKS',
+				blocks: [ {
+					clientId: 'chicken',
+					name: 'core/test-block',
+					attributes: {},
+					innerBlocks: [
+						{
+							clientId: 'child',
+							name: 'core/test-block',
+							attributes: {},
+							innerBlocks: [],
+						},
+					],
+				} ],
+			} );
+			const state = blocks( original, {
+				type: 'REPLACE_BLOCKS',
+				clientIds: [ 'chicken' ],
+				blocks: [ {
+					clientId: 'wings',
+					name: 'core/freeform',
+					innerBlocks: [],
+				} ],
+			} );
+
+			expect( Object.keys( state.byClientId ) ).toHaveLength( 1 );
+			expect( state.order ).toEqual( {
+				'': [ 'wings' ],
+				wings: [],
+			} );
+			expect( state.parents ).toEqual( {
+				wings: '',
+			} );
 		} );
 
 		it( 'should replace the nested block', () => {
@@ -634,6 +709,10 @@ describe( 'state', () => {
 				[ wrapperBlock.clientId ]: [ replacementBlock.clientId ],
 				[ replacementBlock.clientId ]: [],
 			} );
+			expect( state.parents ).toEqual( {
+				[ wrapperBlock.clientId ]: '',
+				[ replacementBlock.clientId ]: wrapperBlock.clientId,
+			} );
 		} );
 
 		it( 'should replace the block even if the new block clientId is the same', () => {
@@ -1024,6 +1103,9 @@ describe( 'state', () => {
 
 			expect( state.order[ '' ] ).toEqual( [ 'ribs' ] );
 			expect( state.order ).not.toHaveProperty( 'chicken' );
+			expect( state.parents ).toEqual( {
+				ribs: '',
+			} );
 			expect( state.byClientId ).toEqual( {
 				ribs: {
 					clientId: 'ribs',
@@ -1063,6 +1145,9 @@ describe( 'state', () => {
 			expect( state.order[ '' ] ).toEqual( [ 'ribs' ] );
 			expect( state.order ).not.toHaveProperty( 'chicken' );
 			expect( state.order ).not.toHaveProperty( 'veggies' );
+			expect( state.parents ).toEqual( {
+				ribs: '',
+			} );
 			expect( state.byClientId ).toEqual( {
 				ribs: {
 					clientId: 'ribs',
@@ -1095,6 +1180,7 @@ describe( 'state', () => {
 			expect( state.order ).toEqual( {
 				'': [],
 			} );
+			expect( state.parents ).toEqual( {} );
 		} );
 
 		it( 'should insert at the specified index', () => {
diff --git a/packages/block-editor/src/store/test/selectors.js b/packages/block-editor/src/store/test/selectors.js
index c038a40621eff..bbb61fbfc04ec 100644
--- a/packages/block-editor/src/store/test/selectors.js
+++ b/packages/block-editor/src/store/test/selectors.js
@@ -156,6 +156,9 @@ describe( 'selectors', () => {
 						'': rootOrder,
 						123: rootBlockOrder,
 					},
+					parents: {
+						123: '',
+					},
 				},
 			};
 
@@ -171,6 +174,9 @@ describe( 'selectors', () => {
 						'': rootOrder,
 						123: rootBlockOrder,
 					},
+					parents: {
+						123: '',
+					},
 				},
 			};
 
@@ -192,6 +198,9 @@ describe( 'selectors', () => {
 						'': rootOrder,
 						123: [],
 					},
+					parents: {
+						123: '',
+					},
 				},
 			};
 
@@ -210,6 +219,10 @@ describe( 'selectors', () => {
 						123: [ 456 ],
 						456: [],
 					},
+					parents: {
+						123: '',
+						456: 123,
+					},
 				},
 			};
 
@@ -239,6 +252,10 @@ describe( 'selectors', () => {
 						123: rootBlockOrder,
 						456: childBlockOrder,
 					},
+					parents: {
+						123: '',
+						456: 123,
+					},
 				},
 			};
 
@@ -257,6 +274,10 @@ describe( 'selectors', () => {
 						123: rootBlockOrder,
 						456: childBlockOrder,
 					},
+					parents: {
+						123: '',
+						456: 123,
+					},
 				},
 			};
 
@@ -284,6 +305,10 @@ describe( 'selectors', () => {
 						123: rootBlockOrder,
 						456: childBlockOrder,
 					},
+					parents: {
+						123: '',
+						456: 123,
+					},
 				},
 			};
 
@@ -302,6 +327,10 @@ describe( 'selectors', () => {
 						123: rootBlockOrder,
 						456: childBlockOrder,
 					},
+					parents: {
+						123: '',
+						456: 123,
+					},
 				},
 			};
 
@@ -335,6 +364,11 @@ describe( 'selectors', () => {
 						456: childBlockOrder,
 						789: grandChildBlockOrder,
 					},
+					parents: {
+						123: '',
+						456: 123,
+						789: 456,
+					},
 				},
 			};
 
@@ -356,6 +390,11 @@ describe( 'selectors', () => {
 						456: childBlockOrder,
 						789: grandChildBlockOrder,
 					},
+					parents: {
+						123: '',
+						456: 123,
+						789: 456,
+					},
 				},
 			};
 
@@ -372,6 +411,7 @@ describe( 'selectors', () => {
 					byClientId: {},
 					attributes: {},
 					order: {},
+					parents: {},
 				},
 			};
 
@@ -396,6 +436,9 @@ describe( 'selectors', () => {
 						'': [ 'afd1cb17-2c08-4e7a-91be-007ba7ddc3a1' ],
 						'afd1cb17-2c08-4e7a-91be-007ba7ddc3a1': [],
 					},
+					parents: {
+						'afd1cb17-2c08-4e7a-91be-007ba7ddc3a1': '',
+					},
 				},
 			};
 
@@ -419,6 +462,9 @@ describe( 'selectors', () => {
 						'': [ 123 ],
 						123: [],
 					},
+					parents: {
+						123: '',
+					},
 				},
 			};
 
@@ -436,6 +482,7 @@ describe( 'selectors', () => {
 					byClientId: {},
 					attributes: {},
 					order: {},
+					parents: {},
 				},
 			};
 
@@ -458,6 +505,10 @@ describe( 'selectors', () => {
 						123: [ 456 ],
 						456: [],
 					},
+					parents: {
+						123: '',
+						456: 123,
+					},
 				},
 			};
 
@@ -507,6 +558,9 @@ describe( 'selectors', () => {
 						'': [ 123 ],
 						123: [],
 					},
+					parents: {
+						123: '',
+					},
 				},
 			};
 
@@ -538,6 +592,10 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 123, 23 ],
 					},
+					parents: {
+						123: '',
+						23: '',
+					},
 				},
 			};
 
@@ -603,6 +661,20 @@ describe( 'selectors', () => {
 						'uuid-26': [ ],
 						'uuid-28': [ 'uuid-30' ],
 					},
+					parents: {
+						'uuid-6': '',
+						'uuid-8': '',
+						'uuid-10': '',
+						'uuid-22': '',
+						'uuid-12': 'uuid-10',
+						'uuid-14': 'uuid-10',
+						'uuid-16': 'uuid-12',
+						'uuid-18': 'uuid-14',
+						'uuid-24': 'uuid-18',
+						'uuid-26': 'uuid-24',
+						'uuid-28': 'uuid-24',
+						'uuid-30': 'uuid-28',
+					},
 				},
 			};
 			expect( getClientIdsOfDescendants( state, [ 'uuid-10' ] ) ).toEqual( [
@@ -673,6 +745,20 @@ describe( 'selectors', () => {
 						'uuid-26': [ ],
 						'uuid-28': [ 'uuid-30' ],
 					},
+					parents: {
+						'uuid-6': '',
+						'uuid-8': '',
+						'uuid-10': '',
+						'uuid-22': '',
+						'uuid-12': 'uuid-10',
+						'uuid-14': 'uuid-10',
+						'uuid-16': 'uuid-12',
+						'uuid-18': 'uuid-14',
+						'uuid-24': 'uuid-18',
+						'uuid-26': 'uuid-24',
+						'uuid-28': 'uuid-24',
+						'uuid-30': 'uuid-28',
+					},
 				},
 			};
 			expect( getClientIdsWithDescendants( state ) ).toEqual( [
@@ -730,6 +816,11 @@ describe( 'selectors', () => {
 						'': [ 123 ],
 						123: [ 456, 789 ],
 					},
+					parents: {
+						123: '',
+						456: 123,
+						789: 123,
+					},
 				},
 			};
 
@@ -788,6 +879,10 @@ describe( 'selectors', () => {
 				order: {
 					'': [ 123, 456 ],
 				},
+				parents: {
+					123: '',
+					456: '',
+				},
 			},
 		};
 
@@ -805,6 +900,7 @@ describe( 'selectors', () => {
 					byClientId: {},
 					attributes: {},
 					order: {},
+					parents: {},
 				},
 			};
 			expect( getGlobalBlockCount( emptyState ) ).toBe( 0 );
@@ -862,6 +958,10 @@ describe( 'selectors', () => {
 						23: [],
 						123: [],
 					},
+					parents: {
+						23: '',
+						123: '',
+					},
 				},
 				blockSelection: { start: {}, end: {} },
 			};
@@ -885,6 +985,10 @@ describe( 'selectors', () => {
 						23: [],
 						123: [],
 					},
+					parents: {
+						123: '',
+						23: '',
+					},
 				},
 				blockSelection: { start: { clientId: 23 }, end: { clientId: 123 } },
 			};
@@ -908,6 +1012,10 @@ describe( 'selectors', () => {
 						23: [],
 						123: [],
 					},
+					parents: {
+						123: '',
+						23: '',
+					},
 				},
 				blockSelection: { start: { clientId: 23 }, end: { clientId: 23 } },
 			};
@@ -926,6 +1034,7 @@ describe( 'selectors', () => {
 			const state = {
 				blocks: {
 					order: {},
+					parents: {},
 				},
 			};
 
@@ -939,10 +1048,16 @@ describe( 'selectors', () => {
 						'': [ 123, 23 ],
 						123: [ 456, 56 ],
 					},
+					parents: {
+						123: '',
+						23: '',
+						456: 123,
+						56: 123,
+					},
 				},
 			};
 
-			expect( getBlockRootClientId( state, 56 ) ).toBe( '123' );
+			expect( getBlockRootClientId( state, 56 ) ).toBe( 123 );
 		} );
 	} );
 
@@ -951,37 +1066,51 @@ describe( 'selectors', () => {
 			const state = {
 				blocks: {
 					order: {},
+					parents: {},
 				},
 			};
 
-			expect( getBlockHierarchyRootClientId( state, 56 ) ).toBe( 56 );
+			expect( getBlockHierarchyRootClientId( state, '56' ) ).toBe( '56' );
 		} );
 
 		it( 'should return root ClientId relative the block ClientId', () => {
 			const state = {
 				blocks: {
 					order: {
-						'': [ 123, 23 ],
-						123: [ 456, 56 ],
+						'': [ 'a', 'b' ],
+						a: [ 'c', 'd' ],
+					},
+					parents: {
+						a: '',
+						b: '',
+						c: 'a',
+						d: 'a',
 					},
 				},
 			};
 
-			expect( getBlockHierarchyRootClientId( state, 56 ) ).toBe( '123' );
+			expect( getBlockHierarchyRootClientId( state, 'c' ) ).toBe( 'a' );
 		} );
 
 		it( 'should return the top level root ClientId relative the block ClientId', () => {
 			const state = {
 				blocks: {
 					order: {
-						'': [ '123', '23' ],
-						123: [ '456', '56' ],
-						56: [ '12' ],
+						'': [ 'a', 'b' ],
+						a: [ 'c', 'd' ],
+						d: [ 'e' ],
+					},
+					parents: {
+						a: '',
+						b: '',
+						c: 'a',
+						d: 'a',
+						e: 'd',
 					},
 				},
 			};
 
-			expect( getBlockHierarchyRootClientId( state, '12' ) ).toBe( '123' );
+			expect( getBlockHierarchyRootClientId( state, 'e' ) ).toBe( 'a' );
 		} );
 	} );
 
@@ -992,6 +1121,10 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 123, 23 ],
 					},
+					parents: {
+						123: '',
+						23: '',
+					},
 				},
 				blockSelection: { start: {}, end: {} },
 			};
@@ -1005,6 +1138,13 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 5, 4, 3, 2, 1 ],
 					},
+					parents: {
+						1: '',
+						2: '',
+						3: '',
+						4: '',
+						5: '',
+					},
 				},
 				blockSelection: { start: { clientId: 2 }, end: { clientId: 2 } },
 			};
@@ -1018,6 +1158,13 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 5, 4, 3, 2, 1 ],
 					},
+					parents: {
+						1: '',
+						2: '',
+						3: '',
+						4: '',
+						5: '',
+					},
 				},
 				blockSelection: { start: { clientId: 2 }, end: { clientId: 4 } },
 			};
@@ -1032,6 +1179,17 @@ describe( 'selectors', () => {
 						'': [ 5, 4, 3, 2, 1 ],
 						4: [ 9, 8, 7, 6 ],
 					},
+					parents: {
+						1: '',
+						2: '',
+						3: '',
+						4: '',
+						5: '',
+						6: 4,
+						7: 4,
+						8: 4,
+						9: 4,
+					},
 				},
 				blockSelection: { start: { clientId: 7 }, end: { clientId: 9 } },
 			};
@@ -1047,6 +1205,10 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 123, 23 ],
 					},
+					parents: {
+						23: '',
+						123: '',
+					},
 				},
 				blockSelection: { start: {}, end: {} },
 			};
@@ -1060,6 +1222,13 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 5, 4, 3, 2, 1 ],
 					},
+					parents: {
+						1: '',
+						2: '',
+						3: '',
+						4: '',
+						5: '',
+					},
 				},
 				blockSelection: { start: { clientId: 2 }, end: { clientId: 4 } },
 			};
@@ -1074,6 +1243,17 @@ describe( 'selectors', () => {
 						'': [ 5, 4, 3, 2, 1 ],
 						4: [ 9, 8, 7, 6 ],
 					},
+					parents: {
+						1: '',
+						2: '',
+						3: '',
+						4: '',
+						5: '',
+						6: 4,
+						7: 4,
+						8: 4,
+						9: 4,
+					},
 				},
 				blockSelection: { start: { clientId: 7 }, end: { clientId: 9 } },
 			};
@@ -1089,6 +1269,7 @@ describe( 'selectors', () => {
 					byClientId: {},
 					attributes: {},
 					order: {},
+					parents: {},
 				},
 				blockSelection: { start: {}, end: {} },
 			};
@@ -1142,6 +1323,10 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 123, 23 ],
 					},
+					parents: {
+						23: '',
+						123: '',
+					},
 				},
 			};
 
@@ -1155,6 +1340,11 @@ describe( 'selectors', () => {
 						'': [ 123, 23 ],
 						123: [ 456 ],
 					},
+					parents: {
+						23: '',
+						123: '',
+						456: 123,
+					},
 				},
 			};
 
@@ -1169,6 +1359,10 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 123, 23 ],
 					},
+					parents: {
+						23: '',
+						123: '',
+					},
 				},
 			};
 
@@ -1182,6 +1376,12 @@ describe( 'selectors', () => {
 						'': [ 123, 23 ],
 						123: [ 456, 56 ],
 					},
+					parents: {
+						23: '',
+						123: '',
+						56: 123,
+						456: 123,
+					},
 				},
 			};
 
@@ -1196,6 +1396,10 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 123, 23 ],
 					},
+					parents: {
+						23: '',
+						123: '',
+					},
 				},
 			};
 
@@ -1209,6 +1413,12 @@ describe( 'selectors', () => {
 						'': [ 123, 23 ],
 						123: [ 456, 56 ],
 					},
+					parents: {
+						23: '',
+						123: '',
+						456: 123,
+						56: 123,
+					},
 				},
 			};
 
@@ -1221,6 +1431,10 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 123, 23 ],
 					},
+					parents: {
+						23: '',
+						123: '',
+					},
 				},
 			};
 
@@ -1234,6 +1448,12 @@ describe( 'selectors', () => {
 						'': [ 123, 23 ],
 						123: [ 456, 56 ],
 					},
+					parents: {
+						23: '',
+						123: '',
+						456: 123,
+						56: 123,
+					},
 				},
 			};
 
@@ -1248,6 +1468,10 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 123, 23 ],
 					},
+					parents: {
+						23: '',
+						123: '',
+					},
 				},
 			};
 
@@ -1261,6 +1485,12 @@ describe( 'selectors', () => {
 						'': [ 123, 23 ],
 						123: [ 456, 56 ],
 					},
+					parents: {
+						23: '',
+						123: '',
+						456: 123,
+						56: 123,
+					},
 				},
 			};
 
@@ -1273,6 +1503,10 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 123, 23 ],
 					},
+					parents: {
+						23: '',
+						123: '',
+					},
 				},
 			};
 
@@ -1286,6 +1520,12 @@ describe( 'selectors', () => {
 						'': [ 123, 23 ],
 						123: [ 456, 56 ],
 					},
+					parents: {
+						23: '',
+						123: '',
+						456: 123,
+						56: 123,
+					},
 				},
 			};
 
@@ -1327,6 +1567,11 @@ describe( 'selectors', () => {
 					order: {
 						4: [ 3, 2, 1 ],
 					},
+					parents: {
+						1: 4,
+						2: 4,
+						3: 4,
+					},
 				},
 			};
 
@@ -1340,6 +1585,11 @@ describe( 'selectors', () => {
 					order: {
 						4: [ 3, 2, 1 ],
 					},
+					parents: {
+						1: 4,
+						2: 4,
+						3: 4,
+					},
 				},
 			};
 
@@ -1352,6 +1602,13 @@ describe( 'selectors', () => {
 					order: {
 						6: [ 5, 4, 3, 2, 1 ],
 					},
+					parents: {
+						1: 6,
+						2: 6,
+						3: 6,
+						4: 6,
+						5: 6,
+					},
 				},
 				blockSelection: { start: { clientId: 2 }, end: { clientId: 4 } },
 			};
@@ -1365,6 +1622,12 @@ describe( 'selectors', () => {
 						3: [ 2, 1 ],
 						6: [ 5, 4 ],
 					},
+					parents: {
+						1: 3,
+						2: 3,
+						4: 6,
+						5: 6,
+					},
 				},
 				blockSelection: { start: { clientId: 5 }, end: { clientId: 4 } },
 			};
@@ -1380,6 +1643,13 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 5, 4, 3, 2, 1 ],
 					},
+					parents: {
+						1: '',
+						2: '',
+						3: '',
+						4: '',
+						5: '',
+					},
 				},
 			};
 
@@ -1393,6 +1663,13 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 5, 4, 3, 2, 1 ],
 					},
+					parents: {
+						1: '',
+						2: '',
+						3: '',
+						4: '',
+						5: '',
+					},
 				},
 			};
 
@@ -1406,6 +1683,13 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 5, 4, 3, 2, 1 ],
 					},
+					parents: {
+						1: '',
+						2: '',
+						3: '',
+						4: '',
+						5: '',
+					},
 				},
 			};
 
@@ -1419,6 +1703,13 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 5, 4, 3, 2, 1 ],
 					},
+					parents: {
+						1: '',
+						2: '',
+						3: '',
+						4: '',
+						5: '',
+					},
 				},
 			};
 
@@ -1467,6 +1758,13 @@ describe( 'selectors', () => {
 				order: {
 					'': [ 5, 4, 3, 2, 1 ],
 				},
+				parents: {
+					1: '',
+					2: '',
+					3: '',
+					4: '',
+					5: '',
+				},
 			},
 			blockSelection: { start: { clientId: 2 }, end: { clientId: 4 } },
 		};
@@ -1486,6 +1784,13 @@ describe( 'selectors', () => {
 				order: {
 					'': [ 5, 4, 3, 2, 1 ],
 				},
+				parents: {
+					1: '',
+					2: '',
+					3: '',
+					4: '',
+					5: '',
+				},
 			},
 			blockSelection: { start: { clientId: 2 }, end: { clientId: 4 } },
 		};
@@ -1598,6 +1903,10 @@ describe( 'selectors', () => {
 						clientId1: [ 'clientId2' ],
 						clientId2: [],
 					},
+					parents: {
+						clientId1: '',
+						clientId2: 'clientId1',
+					},
 				},
 				insertionPoint: {
 					rootClientId: undefined,
@@ -1628,6 +1937,9 @@ describe( 'selectors', () => {
 						'': [ 'clientId1' ],
 						clientId1: [],
 					},
+					parents: {
+						clientId1: '',
+					},
 				},
 				insertionPoint: null,
 			};
@@ -1658,6 +1970,10 @@ describe( 'selectors', () => {
 						clientId1: [ 'clientId2' ],
 						clientId2: [],
 					},
+					parents: {
+						clientId1: '',
+						clientId2: 'clientId1',
+					},
 				},
 				insertionPoint: null,
 			};
@@ -1688,6 +2004,10 @@ describe( 'selectors', () => {
 						clientId1: [],
 						clientId2: [],
 					},
+					parents: {
+						clientId1: '',
+						clientId2: '',
+					},
 				},
 				insertionPoint: null,
 			};
@@ -1718,6 +2038,10 @@ describe( 'selectors', () => {
 						clientId1: [],
 						clientId2: [],
 					},
+					parents: {
+						clientId1: '',
+						clientId2: '',
+					},
 				},
 				insertionPoint: null,
 			};
@@ -1921,6 +2245,7 @@ describe( 'selectors', () => {
 						block1: {},
 					},
 					order: {},
+					parents: {},
 				},
 				settings: {
 					__experimentalReusableBlocks: [
@@ -1991,6 +2316,9 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 'block1ref' ],
 					},
+					parents: {
+						block1ref: '',
+					},
 				},
 				settings: {
 					__experimentalReusableBlocks: [
@@ -2051,6 +2379,11 @@ describe( 'selectors', () => {
 						referredBlock2: [ 'childReferredBlock2' ],
 						childReferredBlock2: [ 'grandchildReferredBlock2' ],
 					},
+					parents: {
+						block2ref: '',
+						childReferredBlock2: 'referredBlock2',
+						grandchildReferredBlock2: 'childReferredBlock2',
+					},
 				},
 
 				settings: {
@@ -2094,6 +2427,7 @@ describe( 'selectors', () => {
 						block2: {},
 					},
 					order: {},
+					parents: {},
 				},
 				settings: {
 					__experimentalReusableBlocks: [
@@ -2137,6 +2471,10 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 'block3', 'block4' ],
 					},
+					parents: {
+						block3: '',
+						block4: '',
+					},
 				},
 				settings: {
 					__experimentalReusableBlocks: [
@@ -2214,6 +2552,7 @@ describe( 'selectors', () => {
 					byClientId: {},
 					attributes: {},
 					order: {},
+					parents: {},
 				},
 				preferences: {
 					insertUsage: {},
@@ -2232,6 +2571,7 @@ describe( 'selectors', () => {
 					byClientId: {},
 					attributes: {},
 					order: {},
+					parents: {},
 				},
 				preferences: {
 					insertUsage: {
@@ -2259,6 +2599,9 @@ describe( 'selectors', () => {
 					order: {
 						'': [ 'block1' ],
 					},
+					parents: {
+						block1: '',
+					},
 				},
 				preferences: {
 					insertUsage: {},