Somerville is a borough in Somerset County, New Jersey, United States. As of the 2010 United States Census, the borough's population was 12,098, reflecting a decline of 325 (-2.6%) from the 12,423 counted in the 2000 Census, which had in turn increased by 791 (+6.8%) from the 11,632 counted in the 1990 Census. 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.