MapRegion.cs

using Bing.Maps;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;

namespace MapTest
{
    public sealed partial class MapRegion : Page
    {
        public BlankPage1()
        {
            this.InitializeComponent();
            bingmap.HomeRegion = "US";
        }

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
        }
    }
}