How do you handle 404 pages in Blazor?

The NotFound template section in the App.razor can be used for handling 404 pages. The router shows this content if it hits a route that is not available, which is a 404 page.

<Router AppAssembly="@typeof(Program).Assembly">
    <Found Context="routeData">
        <RouteView RouteData="@routeData" DefaultLayout="@typeof(MainLayout)" />
    </Found>
    <NotFound>
        <LayoutView Layout="@typeof(MainLayout)">
            <p>Handled 404 page</p>
        </LayoutView>
    </NotFound>
</Router>

Create a component Page/Error.razor to display the 404 content. For more information, read about Blazor routing.