The Picatinny Arsenal is an American military research and manufacturing facility located on 6,400 acres (26 km2) of land in Jefferson and Rockaway Township in Morris County, New Jersey, United States, encompassing Picatinny Lake and Lake Denmark. The Arsenal is the headquarters of the US Army Combat Capabilities Development Command Armaments Center. It is known for developing the ubiquitous Picatinny rail, as well as being the Army's center of expertise for small arms cartridge ammunition.

Rockaway Township is a township in Morris County, in the U.S. state of New Jersey. As of the 2020 United States census, the township's population was 25,341, an increase of 1,185 (+4.9%) from the 2010 census count of 24,156, which in turn reflected an increase of 1,226 (+5.3%) from the 22,930 counted in the 2000 census.