I turn to Bizer as the authority on islands. By the Bizer definition, an island must be surrounded by water at high lake in June. Thus, the Krainewood community doesn't qualify.
The list of islands here has none north of the entrance to Ash cove:
http://www.bizer.com/winislan.htm
Note: Ash cove is circled by Hanson Dr., but Hanson Cove is on the opposite side of the neck, adjacent to Greens Basin.