Riverhead is a census-designated place (CDP) within the Town of Riverhead in Suffolk County, New York. Situated at the mouth of the Peconic River which empties into Peconic Bay and at the intersection where the North and South Forks of Long Island split, Riverhead is the official county seat of Suffolk County. The hamlet began with the Suffolk County Court House, a 1727 structure built to serve both the North and South fork. Since that year, Riverhead has served as the seat of Suffolk County, and still contains the primary courts of the region.
Population: 13,299
Zip Code: 11901
Area Code: 631
Elevation: 13′
