diff --git a/configs/mainnet.yaml b/configs/mainnet.yaml
index e86f5b5c66..929d39f8a2 100644
--- a/configs/mainnet.yaml
+++ b/configs/mainnet.yaml
@@ -12,8 +12,8 @@ CONFIG_NAME: 'mainnet'
 
 # Transition
 # ---------------------------------------------------------------
-# TBD, 2**256-2**10 is a placeholder
-TERMINAL_TOTAL_DIFFICULTY: 115792089237316195423570985008687907853269984665640564039457584007913129638912
+# Estimated on Sept 15, 2022
+TERMINAL_TOTAL_DIFFICULTY: 58750000000000000000000
 # By default, don't use these params
 TERMINAL_BLOCK_HASH: 0x0000000000000000000000000000000000000000000000000000000000000000
 TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH: 18446744073709551615
@@ -43,7 +43,7 @@ ALTAIR_FORK_VERSION: 0x01000000
 ALTAIR_FORK_EPOCH: 74240  # Oct 27, 2021, 10:56:23am UTC
 # Bellatrix
 BELLATRIX_FORK_VERSION: 0x02000000
-BELLATRIX_FORK_EPOCH: 18446744073709551615
+BELLATRIX_FORK_EPOCH: 144896  # Sept 6, 2022, 11:34:47am UTC
 # Capella
 CAPELLA_FORK_VERSION: 0x03000000
 CAPELLA_FORK_EPOCH: 18446744073709551615
diff --git a/configs/minimal.yaml b/configs/minimal.yaml
index 0917cfb57f..5dde4b7494 100644
--- a/configs/minimal.yaml
+++ b/configs/minimal.yaml
@@ -12,7 +12,7 @@ CONFIG_NAME: 'minimal'
 
 # Transition
 # ---------------------------------------------------------------
-# TBD, 2**256-2**10 is a placeholder
+# 2**256-2**10 for testing minimal network
 TERMINAL_TOTAL_DIFFICULTY: 115792089237316195423570985008687907853269984665640564039457584007913129638912
 # By default, don't use these params
 TERMINAL_BLOCK_HASH: 0x0000000000000000000000000000000000000000000000000000000000000000
diff --git a/specs/bellatrix/beacon-chain.md b/specs/bellatrix/beacon-chain.md
index 9285594abd..6d39c1ae89 100644
--- a/specs/bellatrix/beacon-chain.md
+++ b/specs/bellatrix/beacon-chain.md
@@ -91,7 +91,7 @@ Bellatrix updates a few configuration values to move penalty parameters to their
 
 | Name | Value |
 | - | - |
-| `TERMINAL_TOTAL_DIFFICULTY` | **TBD** |
+| `TERMINAL_TOTAL_DIFFICULTY` | `58750000000000000000000` (Estimated: Sept 15, 2022)|
 | `TERMINAL_BLOCK_HASH` | `Hash32()` |
 | `TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH` | `FAR_FUTURE_EPOCH` |
 
diff --git a/specs/bellatrix/fork.md b/specs/bellatrix/fork.md
index 5c0e174da9..19700e3839 100644
--- a/specs/bellatrix/fork.md
+++ b/specs/bellatrix/fork.md
@@ -29,7 +29,7 @@ Warning: this configuration is not definitive.
 | Name | Value |
 | - | - |
 | `BELLATRIX_FORK_VERSION` | `Version('0x02000000')` |
-| `BELLATRIX_FORK_EPOCH` | `Epoch(18446744073709551615)` **TBD** |
+| `BELLATRIX_FORK_EPOCH` | `Epoch(144896)` (Sept 6, 2022, 11:34:47am UTC) |
 
 ## Helper functions