Mattituck Airport (FAA LID: 21N) is a privately owned public use airport located one nautical mile (2km) southeast of the central business district of Mattituck, a hamlet in the Town of Southold, Suffolk County, New York, United States.

Mattituck Airport covers an area of 18 acres (7.3ha) at an elevation of 30 feet (9m) above mean sea level. It has one runway designated 1/19 with a 2,200 x 60 ft (671 x 18 m) asphalt surface.