How to configure a URL with 3 levels in ASP.NET MVC?

First, setup your views:

Views\
  Company\
    Index.aspx
    About.aspx
    Mission.aspx
    AnotherAction.aspx

In your GlobalAsax.RegisterRoutes(RouteCollection routes) method:

public static void RegisterRoutes(RouteCollection routes)
{
  // this will match urls starting with company/about, and then will call the particular
  // action (if it exists)
  routes.MapRoute("mission", "company/about/{action}",
        new { controller = "Company"});
  // the default route goes at the end...
  routes.MapRoute(
    "Default",                                              // Route name
    "{controller}/{action}/{id}",                           // URL with parameters
    new { controller = "Home", action = "Index", id = "" }  // Parameter defaults
  );
}

In the controller:

CompanyController
{
  public ViewResult Index() { return View(); }
  public ViewResult About() { return View(); }
  public ViewResult Mission() { return View(); }
  public ViewResult AnotherAction() { return View(); }
}