diff --git a/src/Components/Components/src/NavigationManager.cs b/src/Components/Components/src/NavigationManager.cs
index 1c8c8e01563f..d721133dd02d 100644
--- a/src/Components/Components/src/NavigationManager.cs
+++ b/src/Components/Components/src/NavigationManager.cs
@@ -38,7 +38,7 @@ public event EventHandler<LocationChangedEventArgs> LocationChanged
     /// <summary>
     /// An event that fires when the page is not found.
     /// </summary>
-    public event EventHandler<EventArgs> NotFoundEvent
+    public event EventHandler<NotFoundEventArgs> OnNotFound
     {
         add
         {
@@ -52,7 +52,7 @@ public event EventHandler<EventArgs> NotFoundEvent
         }
     }
 
-    private EventHandler<EventArgs>? _notFound;
+    private EventHandler<NotFoundEventArgs>? _notFound;
 
     // For the baseUri it's worth storing as a System.Uri so we can do operations
     // on that type. System.Uri gives us access to the original string anyway.
@@ -199,11 +199,11 @@ public virtual void Refresh(bool forceReload = false)
     /// <summary>
     /// Handles setting the NotFound state.
     /// </summary>
-    public virtual void NotFound() => NotFoundCore();
+    public void NotFound() => NotFoundCore();
 
     private void NotFoundCore()
     {
-        _notFound?.Invoke(this, new EventArgs());
+        _notFound?.Invoke(this, new NotFoundEventArgs());
     }
 
     /// <summary>
diff --git a/src/Components/Components/src/PublicAPI.Unshipped.txt b/src/Components/Components/src/PublicAPI.Unshipped.txt
index 441f46ffe210..5b2d8d1cec3f 100644
--- a/src/Components/Components/src/PublicAPI.Unshipped.txt
+++ b/src/Components/Components/src/PublicAPI.Unshipped.txt
@@ -1,6 +1,8 @@
 #nullable enable
-Microsoft.AspNetCore.Components.NavigationManager.NotFoundEvent -> System.EventHandler<System.EventArgs!>!
-virtual Microsoft.AspNetCore.Components.NavigationManager.NotFound() -> void
+Microsoft.AspNetCore.Components.NavigationManager.OnNotFound -> System.EventHandler<Microsoft.AspNetCore.Components.Routing.NotFoundEventArgs!>!
+Microsoft.AspNetCore.Components.NavigationManager.NotFound() -> void
+Microsoft.AspNetCore.Components.Routing.NotFoundEventArgs
+Microsoft.AspNetCore.Components.Routing.NotFoundEventArgs.NotFoundEventArgs() -> void
 Microsoft.AspNetCore.Components.Infrastructure.ComponentStatePersistenceManager.ComponentStatePersistenceManager(Microsoft.Extensions.Logging.ILogger<Microsoft.AspNetCore.Components.Infrastructure.ComponentStatePersistenceManager!>! logger, System.IServiceProvider! serviceProvider) -> void
 Microsoft.AspNetCore.Components.Infrastructure.ComponentStatePersistenceManager.SetPlatformRenderMode(Microsoft.AspNetCore.Components.IComponentRenderMode! renderMode) -> void
 Microsoft.AspNetCore.Components.Infrastructure.RegisterPersistentComponentStateServiceCollectionExtensions
diff --git a/src/Components/Components/src/Routing/NotFoundEventArgs.cs b/src/Components/Components/src/Routing/NotFoundEventArgs.cs
new file mode 100644
index 000000000000..637bfd442b70
--- /dev/null
+++ b/src/Components/Components/src/Routing/NotFoundEventArgs.cs
@@ -0,0 +1,16 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.AspNetCore.Components.Routing;
+
+/// <summary>
+/// <see cref="EventArgs" /> for <see cref="NavigationManager.OnNotFound" />.
+/// </summary>
+public sealed class NotFoundEventArgs : EventArgs
+{
+    /// <summary>
+    /// Initializes a new instance of <see cref="NotFoundEventArgs" />.
+    /// </summary>
+    public NotFoundEventArgs()
+    { }
+}
diff --git a/src/Components/Components/src/Routing/Router.cs b/src/Components/Components/src/Routing/Router.cs
index f27226d492a9..7eabfa828aa4 100644
--- a/src/Components/Components/src/Routing/Router.cs
+++ b/src/Components/Components/src/Routing/Router.cs
@@ -105,7 +105,7 @@ public void Attach(RenderHandle renderHandle)
         _baseUri = NavigationManager.BaseUri;
         _locationAbsolute = NavigationManager.Uri;
         NavigationManager.LocationChanged += OnLocationChanged;
-        NavigationManager.NotFoundEvent += OnNotFound;
+        NavigationManager.OnNotFound += OnNotFound;
         RoutingStateProvider = ServiceProvider.GetService<IRoutingStateProvider>();
 
         if (HotReloadManager.Default.MetadataUpdateSupported)
@@ -147,7 +147,7 @@ public async Task SetParametersAsync(ParameterView parameters)
     public void Dispose()
     {
         NavigationManager.LocationChanged -= OnLocationChanged;
-        NavigationManager.NotFoundEvent -= OnNotFound;
+        NavigationManager.OnNotFound -= OnNotFound;
         if (HotReloadManager.Default.MetadataUpdateSupported)
         {
             HotReloadManager.Default.OnDeltaApplied -= ClearRouteCaches;
diff --git a/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.cs b/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.cs
index 428e84d3ead5..965858d807c0 100644
--- a/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.cs
+++ b/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.cs
@@ -83,7 +83,7 @@ internal async Task InitializeStandardComponentServicesAsync(
 
         if (navigationManager != null)
         {
-            navigationManager.NotFoundEvent += SetNotFoundResponse;
+            navigationManager.OnNotFound += SetNotFoundResponse;
         }
 
         var authenticationStateProvider = httpContext.RequestServices.GetService<AuthenticationStateProvider>();