Roxbury Township was formed on December 24, 1740, from portions of Morris Township, and was formally incorporated 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 1749), Washington Township (April 1798), Chester Township (April 1799), Jefferson Township (February 1804), Mount Olive Township (March 1871), Mount Arlington (November 1890) and Netcong (October 1894).
In 1750 the Brookland iron forge was built by Garret Rapalje, a New York businessman, near the southern end of Lake Hopatcong. Roxbury and the surrounding area became an important hub for producing Iron Ore and cannonballs to supply General George Washington and the Continental Army during the Revolutionary War.
The Township has approximately 23,324 people and 8,292 households.