Based on the code you have shown,  City nor USStates are queryable with both needing to be a collection/List<T>  List<City> and a List<USStates>, becuase List<T> implements  IEnumerable and that makes a List<T> queriable by Linq.  I could be wrong, but for sure City is not queryable it looks to me.

https://www.tutorialsteacher.com/csharp/csharp-list

public City City { get; set; }
public USStates USStates { get; set; }

var StateAndCity = (from c in City
                   join st in USState
                   on c.Id equals st.Id
                   orderby c.Description
                   select new { c.Description, st.State }).ToList();
return Page();

I  have attempted to implement this solution, however, I am getting an error "CS1936 Could not find an implementation of the query pattern for source type City.  'Join' not found."

public Cities List <City> { get; set; } = new List<City>();

public States List<USStates> { get; set; } - new List<USStates>();

Now somehow you are going to need to load each collection with the appropriate object, and then you can use Linq to query them.