Manville is a borough in Somerset County, in the U.S. state of New Jersey. The borough is located in the heart of the Raritan Valley region and is a part of the New York metropolitan area. As of the 2020 United States census, the borough's population was 10,953, an increase of 609 from the 2010 census count of 10,344, which in turn reflected an increase of o…Manville is a borough in Somerset County, in the U.S. state of New Jersey. The borough is located in the heart of the Raritan Valley region and is a part of the New York metropolitan area. As of the 2020 United States census, the borough's population was 10,953, an increase of 609 from the 2010 census count of 10,344, which in turn reflected an increase of one person from the 10,343 counted in the 2000 census. Manville was named after the Johns-Manville Corporation, which maintained a large manufacturing facility in the borough for decades.