Hamilton Township is a township and the most populous municipality in Mercer County, in the U.S. state of New Jersey. It is the largest suburb of Trenton, the state's capital, which is located to the township's west. The township is situated within the New York metropolitan area as defined by the United States Census Bureau but directly borders the Philadelphia metropolitan area and is part of the Federal Communications Commission's Philadelphia Designated Market Area. As of the 2020 United States census, the township's population was 92,297, its highest decennial count ever and an increase of 3,833 (+4.3%) from the 2010 census count of 88,464, which in turn reflected an increase of 1,355 (+1.6%) from the 2000 census count of 87,109. The township was the state's ninth-largest municipality in 2010 and 2020, after having been ranked 10th in 2000.

Mercer County is a county located in the U.S. state of New Jersey. Its county seat is Trenton, also the state capital, prompting its nickname The Capital County. Mercer County alone constitutes the Trenton–Princeton metropolitan statistical area and is considered part of the New York combined statistical area by the U.S. Census Bureau, but also directly borders the Philadelphia metropolitan area and is included within the Federal Communications Commission's Philadelphia Designated Media Market Area. The county is part of the Central Jersey region of the state.