Somerville is a borough in Somerset County, New Jersey, United States. As of the 2010 United States Census, the borough population was 12,098. It is the county seat of Somerset County.
Somerville was originally formed as a Town on March 25, 1863, within a portion of Bridgewater Township. Somerville was incorporated as a borough by an Act of the New Jersey Legislature on April 16, 1909, based on the results of a referendum held on May 4, 1909, at which point it was fully set off from Bridgewater Township.
According to the United States Census Bureau, the borough has a total area of 2.4 square miles (6.1 km2).The borough's territory is flat land. Somerville borders the Raritan River to the south.