Rahway is a city in southern Union County, New Jersey, United States. It is part of the New York metropolitan area, being 15 miles (24 km) southwest of Manhattan and 5 miles (8.0 km) west of Staten Island. As of the 2010 United States Census, the city population was 27,346. The population increased by 846 (+3.2%) from the 26,500 counted in the 2000 Census, which had in turn increased by 1,175 (+4.6%) from the 25,325 counted in the 1990 Census.