The North Fork is a 30-mile- (48 km) long peninsula in the northeast part of Suffolk County, New York, U.S., roughly parallel with a longer peninsula known as the South Fork, both on the East End of Long Island. Although the peninsula begins east of Riverhead hamlet, the term North Fork can also refer collectively to the towns of Riverhead and Southold in their entirety.

Suffolk County is the easternmost county in the U.S. state of New York. It is bordered to its west by Nassau County, to its east by Gardiners Bay and the Atlantic Ocean, to its north by Long Island Sound, and to its south by Great South Bay. The county is part of the Long Island region of the state, of which it comprises the eastern two-thirds.