3rd Battalion 12th Marines (3/12) is an artillery battalion comprising three firing batteries and a Headquarters Battery. The firing batteries are all on 6 month rotations in Okinawa from the 10th Marine Regiment and the 11th Marine Regiment (known as the Unit Deployment Program (UDP)). The battalion is stationed at Camp Hansen, Okinawa, Japan and its primary weapon system is the M777 lightweight howitzer with a maximum effective range of 30 km. The battalion utilizes the Unit Deployment Program to fill its three firing batteries with detachments from artillery units across the Marine Corps.