Knowlton Township is a township in Warren County, New Jersey, United States. As of the 2010 United States Census, the township's population was 3,055, reflecting an increase of 78 (+2.6%) from the 2,977 counted in the 2000 Census, which had in turn increased by 434 (+17.1%) from the 2,543 counted in the 1990 Census.
Knowlton Township was created by Royal charter on February 23, 1763, from portions of Oxford Township, while the area was still part of Sussex County, and was incorporated as a township by an Act of the New Jersey Legislature on February 21, 1798, and then became part of the newly created Warren County on November 20, 1824. Portions of the township were taken to form Hope Township (April 8, 1839) and Blairstown Township (April 14, 1845).
Knowlton is named after Thomas Knowlton, a Colonel in the Continental Army during the American Revolutionary War who was killed in action at the Battle of Harlem Heights. The township is served by postal ZIP codes in Columbia (07832) and Delaware (07833), although a small number of Knowlton residents receive postal deliveries via the Blairstown (07825) post office. Within the township are several small hamlets, including Browning, Deckers Ferry, Mount Pleasant, Polkville, Ramseyburg, Warrington and Knowlton itself.