Franklin Township is a township in central Hunterdon County, in the U.S. state of New Jersey. As of the 2020 United States census, the township's population was 3,267, an increase of 72 (+2.3%) from the 2010 census count of 3,195, which in turn reflected an increase of 205 (+6.9%) from the 2,990 counted in the 2000 census. Most of the township lies on the Hunterdon Plateau with only the eastern section along the South Branch Raritan River being on the lower part of the Newark Basin.

Union Township is a township in Hunterdon County, in the U.S. state of New Jersey. The southwest half of the township lies on what is known as the Hunterdon Plateau, the northwest corner consists of the Musconetcong Ridge and the northeast section is part of the lower-lying Newark Basin around Spruce Run Reservoir. As of the 2020 United States census, the township's population was 6,507, its highest ever decennial count and an increase of 599 (+10.1%) from the 2010 census count of 5,908, which in turn reflected a decline of 252 (−4.1%) from the 6,160 counted in the 2000 census.