Castle Island

Castle Island may refer to:

Bermuda

 * Castle Island, Bermuda, one of the islands of Castle Harbour, Bermuda
 * Castle Islands Fortifications, Bermuda

Canada

 * Castle Island, Alberta
 * Castle Island, Manitounuk Islands, Nunavut

Greenland

 * Castle Island (Greenland), an island in Sherard Osborn Fjord

Ireland

 * Castle Island (County Cork), and uninhabited island in Roaringwater Bay (51.507518N, 9.504267W)
 * Castle Island (County Roscommon), an island in Lough Key
 * Castleisland, a town in County Kerry, Ireland

New Zealand

 * Castle Island, New Zealand

United Kingdom

 * Castle Island, County Down, a townland in County Down, Northern Ireland
 * Castle Island, County Antrim, a townland in County Antrim, Northern Ireland
 * Castle Island, Scotland

United States

 * Castle Island (Massachusetts), an island in Boston Harbor
 * Castle Island (New York), formerly an island in the Hudson River currently part of the Port of Albany-Rensselaer in Albany, New York
 * Castle Island (Washington), one of the San Juan Islands