Matawan is a borough in Monmouth County, in the U.S. state of New Jersey. A historic community located near the Raritan Bay in the much larger Raritan Valley region, Raritan Bayshore the borough is a commuter town of New York City within the New York Metropolitan Area. As of the 2020 United States census, the borough's population was 9,565, an increase of 755 (+8.6%) from the 2010 census count of 8,810, which in turn reflected a decline of 100 (−1.1%) from the 8,910 counted in the 2000 census.