By using follwoing code, we can get the Users list url,

SPList userList = SPContext.Current.Web.SiteUserInfoList;
string url = userList.Forms[PAGETYPE.PAGE_DISPLAYFORM].Url;

the above code will return like the following url http://mysite/_layouts/userdisp.aspx. But, this url is not the exact url.

The actual url for “User Information List” available under _Catalogs folder.
FYI, I list out the url’s here,

• http://mysite/_catalogs/users/detail.aspx
              Shows the detail view of only Users in the list.
• http://mysite/_catalogs/users/simple.aspx
              Shows the simple view of only Users in the List
• http://mysite/_catalogs/users/allgroups.aspx
              Shows all the groups without users available in Site.

In my next post, i’ll explain about the default folders available in this “User Information List”.