Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Andover Township is a Township in Sussex County, New Jersey, United States. As of the United States 2000 Census, the township population was 6,033.Andover was incorporated as a township by an Act of the New Jersey Legislature on April 11, 1864, from portions of Newton Township, which was split up on that date and dissolved. Portions of the township were taken to form Fredon Township (February 24, 1904) and Andover borough (March 25, 1904). Portions of the township were ceded to Newton town in both 1869 and 1927.The township was suggestively named after the existing village of Andover, whose name origin is unknown.