West Windsor Township is a township in Mercer County, New Jersey, in the United States. As of the 2010 United States Census, the township's population was 27,165, reflecting an increase of 5,258 (+24.0%) from the 21,907 counted in the 2000 Census, which had in turn increased by 5,886 (+36.7%) from the 16,021 counted in the 1990 Census.