diff --git a/src/Microsoft.AspNetCore.Blazor/RenderTree/RenderTreeBuilder.cs b/src/Microsoft.AspNetCore.Blazor/RenderTree/RenderTreeBuilder.cs
index f71cc4c92a..4b5f7e6bb2 100644
--- a/src/Microsoft.AspNetCore.Blazor/RenderTree/RenderTreeBuilder.cs
+++ b/src/Microsoft.AspNetCore.Blazor/RenderTree/RenderTreeBuilder.cs
@@ -201,22 +201,17 @@ namespace Microsoft.AspNetCore.Blazor.RenderTree
             entry = entry.WithComponentSubtreeLength(_entries.Count - indexOfEntryBeingClosed);
         }
 
-        /// <summary>
-        /// Appends a frame denoting the start of a region (that is, a tree fragment that is
-        /// processed as a unit for the purposes of diffing).
-        /// </summary>
-        /// <param name="sequence">An integer that represents the position of the instruction in the source code.</param>
-        public void OpenRegion(int sequence)
+        // Internal for tests
+        // Not public because there's no current use case for user code defining regions arbitrarily.
+        // Currently the sole use case for regions is when appending a RenderFragment.
+        internal void OpenRegion(int sequence)
         {
             _openElementIndices.Push(_entries.Count);
             Append(RenderTreeFrame.Region(sequence));
         }
 
-        /// <summary>
-        /// Marks a previously appended region frame as closed. Calls to this method
-        /// must be balanced with calls to <see cref="OpenRegion"/>.
-        /// </summary>
-        public void CloseRegion()
+        // See above for why this is not public
+        internal void CloseRegion()
         {
             var indexOfEntryBeingClosed = _openElementIndices.Pop();
             ref var entry = ref _entries.Buffer[indexOfEntryBeingClosed];
diff --git a/test/testapps/BasicTestApp/RenderBlockComponent.cs b/test/testapps/BasicTestApp/RenderBlockComponent.cs
index 7088aad36d..ff68bc5846 100644
--- a/test/testapps/BasicTestApp/RenderBlockComponent.cs
+++ b/test/testapps/BasicTestApp/RenderBlockComponent.cs
@@ -43,22 +43,20 @@ namespace BasicTestApp
         private void Render() => _renderHandle.Render(builder =>
         {
             builder.OpenElement(0, "div"); // Container so we can see that passing through regions is OK
-            builder.OpenRegion(1);
-            builder.AddContent(2, "Region will be toggled below ");
+            builder.AddContent(1, "Region will be toggled below ");
 
             if (_showRegion)
             {
-                builder.AddContent(3, _exampleContent);
+                builder.AddContent(2, _exampleContent);
             }
 
-            builder.OpenElement(4, "button");
-            builder.AddAttribute(5, "onclick", ToggleRegion);
-            builder.AddContent(6, "Toggle");
+            builder.OpenElement(3, "button");
+            builder.AddAttribute(4, "onclick", ToggleRegion);
+            builder.AddContent(5, "Toggle");
             builder.CloseElement();
 
-            builder.CloseRegion();
-            builder.OpenElement(7, "p");
-            builder.AddContent(8, "The end");
+            builder.OpenElement(6, "p");
+            builder.AddContent(7, "The end");
             builder.CloseElement();
             builder.CloseElement();
         });