Sprouts of the Mohawk River

[6] The sprout separating Green Island from the rest of Albany County was filled in with the creation of Interstate 787 and NY Route 787.

The Native Americans called the area Nach-te-Nack, and by the Dutch settlers Halve-Maen (translated as Halfmoon in English).

[3] The fords connecting the islands were used by the local Native Americans, the Mohicans and by the Dutch and English at Fort Orange and Albany en route to Montreal and Canada, being used by soldiers in the French and Indian Wars.

During the American Revolutionary War the islands were the site of military fortifications protecting the fords and river road leading to Albany from invasion forces coming from Canada.

[12] The name Fourth Branch is still used in reference to the hydroelectric power plant located in the town of Waterford.

The New York State Office of Parks, Recreation and Historic Preservation headquarters is located on the island.