Cranbury is a township in Middlesex County, New Jersey, United States. Located within the Raritan Valley region, Cranbury is roughly equidistant between New York City and Philadelphia in the heart of the state. As of the 2010 United States Census, the township's population was 3,857, reflecting an increase of 630 (+19.5%) from the 3,227 counted in the 2000 Census, which had in turn increased by 727 (+29.1%) from the 2,500 counted in 1990.