Roxbury Township is a township in Morris County, New Jersey, United States. As of the 2010 United States Census, the township's population was 23,324, reflecting a decline of 559 (-2.3%) from the 23,883 counted in the 2000 Census, which had in turn increased by 3,454 (+16.9%) from the 20,429 counted in the 1990 Census. Roxbury Township is located approximately west-northwest of New York City, west-northwest of Newark, New Jersey and east of the Delaware Water Gap on the border of New Jersey and Pennsylvania.
Roxbury Township was formed on December 24, 1740, from portions of Morris Township, and was formally incorporated as a township by an Act of the New Jersey Legislature on February 21, 1798, as part of the state's initial group of 104 townships. Portions of the township were taken to form Mendham Township (March 29, 1749), Washington Township (April 2, 1798), Chester Township (April 1, 1799), Jefferson Township (February 11, 1804), Mount Olive Township (March 22, 1871), Mount Arlington (November 3, 1890) and Netcong (October 23, 1894).
Kenvil (2010 Census population of 3,009) and Succasunna (2010 Census population of 9,152) are census-designated places and unincorporated communities located within the township. As of the 2000 United States Census, the two CDPs were consolidated as Succasunna-Kenvil, which had a 2000 Census population of 12,569. The Township of Roxbury includes other unincorporated communities and neighborhoods including Berkshire Valley, Landing, Ledgewood and Port Morris.