public class StatesViewModel
{
    public string StateCode { get; set; }
}

var QryStates = from s in _context.States
             where s.StateAbrv != null && s.StateAbrv != string.Empty
             select new { s.StateAbrv };

var QryCustCount = (from c in ontext.Customers
        join qs in QryStates on c.StateAbrv equals qs.StateAbrv
        group qs by new { qs.StateAbrv } into grpStateAbrv
        select new StatesViewModel{ StateCode = grpStateAbrv.Key.Statecd }).ToList();