Adelphia is an unincorporated community located in northern Howell Township, Monmouth County, in the U.S. state of New Jersey. The area is served as United States Postal Service ZIP code 07710. The community borders Freehold Township, and residents who reside in Adelphia use a Freehold mailing address.

Howell Township is a township in Monmouth County, in the U.S. state of New Jersey. The township is the largest municipality in the county by total area, comprised of about 61.21 square miles (158.5 km2). It is located in the New York metropolitan area and has been a steadily growing bedroom community of New York City. As of the 2020 United States census, the township's population was 53,537, its highest decennial count ever and an increase of 2,462 (+4.8%) from the 2010 census count of 51,075, which in turn reflected an increase of 2,172 (+4.4%) from the 48,903 counted in the 2000 census.