Walpack Township is a township in Sussex County, in the U.S. state of New Jersey. As of the 2020 United States census, the township's population was 7, a decrease of 9 (−56.3%) from the 2010 census count of 16, which in turn reflected a decline of 34 (−82.9%) from the 41 counted in the 2000 census. Walpack Township was the smallest municipality by population and one of only four municipalities in New Jersey with a population under 100 as of the 2020 Census; it had the state's third-smallest population in the 2010 census, behind Tavistock (population 5) and the now-defunct Pine Valley (population 12), both in Camden County.
The township is named from a corruption of the Lenape Native American content word "wahlpeck," which means "turn-hole," or an eddy or whirlpool, a compound of two Native American words, "woa-lac" (a hole), and "tuppeck" (a pool), though other sources attribute the name to mean "very deep water" or "sudden bend of a stream around the base of a rock".
