Redirect to a hash from the controller using "RedirectToAction"

Hello I want to return an anchor from Mvc Controller

Controller name= DefaultController;

public ActionResult MyAction(int id)
{
        return RedirectToAction("Index", "region")
}

So that the url when directed to index is

http://localhost/Default/#region

So that

<a href=#region>the content should be focus here</a>

I am not asking if you can do it like this: How can I add an anchor tag to my URL?