diff --git a/StyleCop.Analyzers/StyleCop.Analyzers.CodeFixes/LayoutRules/SA1516CodeFixProvider.cs b/StyleCop.Analyzers/StyleCop.Analyzers.CodeFixes/LayoutRules/SA1516CodeFixProvider.cs
index 73c5bcfb7..b8d7940fa 100644
--- a/StyleCop.Analyzers/StyleCop.Analyzers.CodeFixes/LayoutRules/SA1516CodeFixProvider.cs
+++ b/StyleCop.Analyzers/StyleCop.Analyzers.CodeFixes/LayoutRules/SA1516CodeFixProvider.cs
@@ -152,6 +152,11 @@ private static SyntaxNode GetRelevantNode(SyntaxNode innerNode)
                     return currentNode;
                 }
 
+                if (currentNode is ExternAliasDirectiveSyntax)
+                {
+                    return currentNode;
+                }
+
                 currentNode = currentNode.Parent;
             }
 
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp10/LayoutRules/SA1516CSharp10UnitTests.cs b/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp10/LayoutRules/SA1516CSharp10UnitTests.cs
index baa1ba110..f6020b139 100644
--- a/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp10/LayoutRules/SA1516CSharp10UnitTests.cs
+++ b/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp10/LayoutRules/SA1516CSharp10UnitTests.cs
@@ -3,9 +3,241 @@
 
 namespace StyleCop.Analyzers.Test.CSharp10.LayoutRules
 {
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis;
+    using Microsoft.CodeAnalysis.CSharp;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp9.LayoutRules;
+    using Xunit;
+    using static StyleCop.Analyzers.Test.Verifiers.StyleCopCodeFixVerifier<
+        StyleCop.Analyzers.LayoutRules.SA1516ElementsMustBeSeparatedByBlankLine,
+        StyleCop.Analyzers.LayoutRules.SA1516CodeFixProvider>;
 
     public class SA1516CSharp10UnitTests : SA1516CSharp9UnitTests
     {
+        /// <summary>
+        /// Verifies that SA1516 is reported for usings and extern alias outside a file scoped namespace.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3512, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3512")]
+        public async Task TestThatDiagnosticIIsReportedOnUsingsAndExternAliasOutsideFileScopedNamespaceAsync()
+        {
+            var testCode = @"extern alias corlib;
+[|using|] System;
+using System.Linq;
+using a = System.Collections;
+[|namespace|] Foo;
+";
+
+            var fixedCode = @"extern alias corlib;
+
+using System;
+using System.Linq;
+using a = System.Collections;
+
+namespace Foo;
+";
+
+            await VerifyCSharpFixAsync(testCode, fixedCode).ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Verifies that SA1516 is reported for usings inside a file scoped namespace.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3512, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3512")]
+        public async Task TestThatDiagnosticIIsReportedOnSpacingWithUsingsInsideFileScopedNamespaceAsync()
+        {
+            var testCode = @"namespace Foo;
+[|using|] System;
+using System.Linq;
+using a = System.Collections;
+";
+
+            var fixedCode = @"namespace Foo;
+
+using System;
+using System.Linq;
+using a = System.Collections;
+";
+
+            await VerifyCSharpFixAsync(testCode, fixedCode).ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Verifies that SA1516 is reported for member declarations inside a file scoped namespace.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3512, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3512")]
+        public async Task TestThatDiagnosticIIsReportedOnMemberDeclarationsInsideFileScopedNamespaceAsync()
+        {
+            var testCode = @"namespace Foo;
+[|public|] class Bar
+{
+}
+[|public|] enum Foobar
+{
+}
+";
+
+            var fixedCode = @"namespace Foo;
+
+public class Bar
+{
+}
+
+public enum Foobar
+{
+}
+";
+
+            await VerifyCSharpFixAsync(testCode, fixedCode).ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Verifies that SA1516 is reported for usings and member declarations inside a file scoped namespace.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3512, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3512")]
+        public async Task TestThatDiagnosticIIsReportedOnUsingsAndMemberDeclarationsInsideFileScopedNamespaceAsync()
+        {
+            var testCode = @"namespace Foo;
+[|using|] System;
+using System.Linq;
+using a = System.Collections;
+[|public|] class Bar
+{
+}
+[|public|] enum Foobar
+{
+}
+";
+
+            var fixedCode = @"namespace Foo;
+
+using System;
+using System.Linq;
+using a = System.Collections;
+
+public class Bar
+{
+}
+
+public enum Foobar
+{
+}
+";
+
+            await VerifyCSharpFixAsync(testCode, fixedCode).ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Verifies that SA1516 is reported extern alias inside a file scoped namespace.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3512, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3512")]
+        public async Task TestThatDiagnosticIIsReportedOnExternAliasInsideFileScopedNamespaceAsync()
+        {
+            var testCode = @"namespace Foo;
+[|extern|] alias corlib;
+";
+
+            var fixedCode = @"namespace Foo;
+
+extern alias corlib;
+";
+
+            await VerifyCSharpFixAsync(testCode, fixedCode).ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Verifies that SA1516 is reported extern alias and usings inside a file scoped namespace.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3512, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3512")]
+        public async Task TestThatDiagnosticIIsReportedOnExternAliasAndUsingsInsideFileScopedNamespaceAsync()
+        {
+            var testCode = @"namespace Foo;
+[|extern|] alias corlib;
+[|using|] System;
+using System.Linq;
+using a = System.Collections;
+";
+
+            var fixedCode = @"namespace Foo;
+
+extern alias corlib;
+
+using System;
+using System.Linq;
+using a = System.Collections;
+";
+
+            await VerifyCSharpFixAsync(testCode, fixedCode).ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Verifies that SA1516 is reported extern alias, usings and member declarations
+        /// inside a file scoped namespace.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3512, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3512")]
+        public async Task TestThatDiagnosticIIsReportedOnExternAliasUsingsAndMemberDeclarationsInsideFileScopedNamespaceAsync()
+        {
+            var testCode = @"namespace Foo;
+[|extern|] alias corlib;
+[|using|] System;
+using System.Linq;
+using a = System.Collections;
+[|public|] class Bar
+{
+}
+[|public|] enum Foobar
+{
+}
+";
+
+            var fixedCode = @"namespace Foo;
+
+extern alias corlib;
+
+using System;
+using System.Linq;
+using a = System.Collections;
+
+public class Bar
+{
+}
+
+public enum Foobar
+{
+}
+";
+
+            await VerifyCSharpFixAsync(testCode, fixedCode).ConfigureAwait(false);
+        }
+
+        private static Task VerifyCSharpFixAsync(string testCode, string fixedCode)
+        {
+            var test = new CSharpTest
+            {
+                ReferenceAssemblies = ReferenceAssemblies.Net.Net60,
+                TestState =
+                {
+                    Sources = { testCode },
+                },
+                FixedCode = fixedCode,
+            };
+
+            return test.RunAsync(CancellationToken.None);
+        }
     }
 }
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/LayoutRules/SA1516ElementsMustBeSeparatedByBlankLine.cs b/StyleCop.Analyzers/StyleCop.Analyzers/LayoutRules/SA1516ElementsMustBeSeparatedByBlankLine.cs
index bd1ea17ea..2ac731989 100644
--- a/StyleCop.Analyzers/StyleCop.Analyzers/LayoutRules/SA1516ElementsMustBeSeparatedByBlankLine.cs
+++ b/StyleCop.Analyzers/StyleCop.Analyzers/LayoutRules/SA1516ElementsMustBeSeparatedByBlankLine.cs
@@ -15,6 +15,7 @@ namespace StyleCop.Analyzers.LayoutRules
     using Microsoft.CodeAnalysis.Diagnostics;
     using Microsoft.CodeAnalysis.Text;
     using StyleCop.Analyzers.Helpers;
+    using StyleCop.Analyzers.Lightup;
     using StyleCop.Analyzers.Settings.ObjectModel;
 
     /// <summary>
@@ -87,6 +88,7 @@ internal class SA1516ElementsMustBeSeparatedByBlankLine : DiagnosticAnalyzer
         private static readonly Action<SyntaxNodeAnalysisContext> TypeDeclarationAction = HandleTypeDeclaration;
         private static readonly Action<SyntaxNodeAnalysisContext, StyleCopSettings> CompilationUnitAction = HandleCompilationUnit;
         private static readonly Action<SyntaxNodeAnalysisContext, StyleCopSettings> NamespaceDeclarationAction = HandleNamespaceDeclaration;
+        private static readonly Action<SyntaxNodeAnalysisContext, StyleCopSettings> FileScopedNamespaceDeclarationAction = HandleFileScopedNamespaceDeclaration;
         private static readonly Action<SyntaxNodeAnalysisContext> BasePropertyDeclarationAction = HandleBasePropertyDeclaration;
 
         private static readonly ImmutableDictionary<string, string> DiagnosticProperties = ImmutableDictionary<string, string>.Empty.Add(CodeFixActionKey, InsertBlankLineValue);
@@ -129,6 +131,7 @@ public override void Initialize(AnalysisContext context)
                 context.RegisterSyntaxNodeAction(TypeDeclarationAction, SyntaxKinds.TypeDeclaration);
                 context.RegisterSyntaxNodeAction(CompilationUnitAction, SyntaxKind.CompilationUnit);
                 context.RegisterSyntaxNodeAction(NamespaceDeclarationAction, SyntaxKind.NamespaceDeclaration);
+                context.RegisterSyntaxNodeAction(FileScopedNamespaceDeclarationAction, SyntaxKindEx.FileScopedNamespaceDeclaration);
                 context.RegisterSyntaxNodeAction(BasePropertyDeclarationAction, SyntaxKinds.BasePropertyDeclaration);
             });
         }
@@ -212,6 +215,42 @@ private static void HandleCompilationUnit(SyntaxNodeAnalysisContext context, Sty
             }
         }
 
+        private static void HandleFileScopedNamespaceDeclaration(SyntaxNodeAnalysisContext context, StyleCopSettings settings)
+        {
+            var namespaceDeclaration = (BaseNamespaceDeclarationSyntaxWrapper)context.Node;
+
+            var usings = namespaceDeclaration.Usings;
+            var members = namespaceDeclaration.Members;
+
+            HandleUsings(context, usings, settings);
+            HandleMemberList(context, members);
+
+            if (namespaceDeclaration.Externs.Count > 0)
+            {
+                ReportIfThereIsNoBlankLine(context, namespaceDeclaration.Name, namespaceDeclaration.Externs[0]);
+            }
+
+            if (namespaceDeclaration.Usings.Count > 0)
+            {
+                ReportIfThereIsNoBlankLine(context, namespaceDeclaration.Name, namespaceDeclaration.Usings[0]);
+
+                if (namespaceDeclaration.Externs.Count > 0)
+                {
+                    ReportIfThereIsNoBlankLine(context, namespaceDeclaration.Externs[namespaceDeclaration.Externs.Count - 1], namespaceDeclaration.Usings[0]);
+                }
+            }
+
+            if (members.Count > 0)
+            {
+                ReportIfThereIsNoBlankLine(context, namespaceDeclaration.Name, members[0]);
+
+                if (namespaceDeclaration.Usings.Count > 0)
+                {
+                    ReportIfThereIsNoBlankLine(context, usings[usings.Count - 1], members[0]);
+                }
+            }
+        }
+
         private static void HandleNamespaceDeclaration(SyntaxNodeAnalysisContext context, StyleCopSettings settings)
         {
             var namespaceDeclaration = (NamespaceDeclarationSyntax)context.Node;