City Island is a neighborhood in the northeastern Bronx in New York City, located on an island of the same name approximately 1.5 miles (2.4 km) long^[3] by 0.5 miles (0.80 km) wide. City Island is located at the extreme western end of Long Island Sound,^[3] south of Pelham Bay and east of Eastchester Bay.

At one time the island was incorporated within the boundaries of Pelham, Westchester County, New York, but the island is now part of New York City. City Island is part of the Pelham Islands, a group of islands that once belonged to Thomas Pell. The body of water between City Island and the even smaller, uninhabited Hart Island to the east is known as City Island Harbor. The small island adjacent to the northeast is High Island. The Stepping Stones Light, marking the main shipping channel into New York, is off the southern tip of City Island, near the Long Island shore.