The Picatinny Arsenal is an installation in northwest New Jersey, in the United States of America. It is a military facility, and has been since it was established in 1880 as the "Dover Powder Depot." Four days after it was named, it was changed to the "Picatinny Powder Depot." Under both names, it was established as a manufactory and storage facility for gunpowder for use by the U.S. Military. In 1907, the first production plant in the U.S. for nitrocellulose (also known as smokeless powder) was built within its bounds, and the name was changed to the current Picatinny Arsenal.

During World War I, a school for weaponry-related sciences for officers was set up, as was a small laboratory for researching weapon effects and substances. A small experimental setup for manufacturing artillery projectiles was set up just after the war, and the Picatinny Arsenal began to transform into the central weapons technology research facility it is today. It is known for many things by many different types of people. Firearms enthusiasts will probably recognize the name from the Picatinny Rail, also known as the MIL-ST-1913 rail - a standardized firearms mounting system for the attachment of accessories such as sights, scopes and illuminators used to this day. The Arsenal, during the interwar period, began to work on 'hard' weapon systems with the introduction there of work on fuzing systems which has continued to the present. During World War II, the research and development arms of the arsenal flagged a bit with good reason. It was the only facility in the continental U.S. capable of manufacturing large-caliber ammunition (larger than Browning 50-caliber shells) at the start of the war; production techniques and setups for all manner of artillery and mortar shells as well as those for automatic cannons were initiated at Picatinny before sometimes being moved or copied to other locations. Three shifts and over 18,000 workers labored there during the war.

Following World War II, the facility took the lead in the research and development of the ever-more-advanced weapon systems that the U.S. Army started to field. Its research on everything from new ways to manufacture explosives such as RDX to the discovery and weaponization of new explosive compounds coupled with its fuzing experience made it a natural home for the development of ammunition and bombs. Today, Picatinny Arsenal calls itself 'The Home of American Firepower' and is actively involved in the development of everything from 'smart' tank shells (120mm MRM) to tank-seeking artillery shells (Copperhead, SADARM) and all manner of infantry weapons from rifles to grenade launchers and their loads.

The arsenal is located on a plot of approximately 6,500 acres in the Picatinny Valley, and is the home (presently) of the oft-renamed Armament Research and Development Center. It is a couple of hours' drive from the New York City metropolitan area, making it a popular duty station.