using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        List<Test> Collection = new List<Test>();

        Dictionary<string,List<Test>> test = (from tst in Collection

                group tst by tst.Location into grp

                select grp).ToDictionary(x=> x.Key, x=> x.ToList());

    }

    public class Test{

        public string Location {get;set;}

        public string OtherField {get;set;}

        public string AnotherField {get;set;}

    }

}