Raritan is a borough in Somerset County, New Jersey, United States. As of the 2010 United States Census, the borough's population was 6,881, reflecting an increase of 543 from the 6,338 counted in the 2000 Census, which had in turn increased by 540 from the 5,798 counted in the 1990 Census.The township's name is derived from the Raritans, a Native American group of Lenapes. The name of the tribe is said to mean "forked river", "stream overflows" or "point on a tidal river".