On February 21, 1798, Acquackanonk was incorporated as one of the initial group of 104 townships in the State of New Jersey. On February 7, 1837, Passaic County was created, incorporating the township and other portions of both Bergen County and Essex County. Over the years portions of the township were taken to create (or add to the territory of) Caldwell Township (February 16, 1798; now Fairfield Township), Paterson Township (April 11, 1831), Little Falls (April 2, 1868), Passaic village (created within the township on March 10, 1869, and independent from the township as of March 21, 1871), Paterson (1869) and Montclair (1907). The township became defunct on April 26, 1917, with the creation of Clifton.