Marine Medium Tiltrotor Squadron 161 (VMM-161) is a United States Marine Corps transport squadron consisting of MV-22 Osprey tiltrotor aircraft. The squadron, known as the "Greyhawks", is based at Marine Corps Air Station Miramar, California and falls under the command of Marine Aircraft Group 16 (MAG-16) and the 3rd Marine Aircraft Wing (3rd MAW). The squadron has the distinction of being the first helicopter transport squadron in the world.
The squadron was activated on January 15, 1951 at Marine Corps Air Station El Toro, California, as Marine Helicopter Transport Squadron 161 (HMR-161) Air Fleet Marine Force Pacific, the squadron moved a month later to Marine Corps Air Facility, Santa Ana, California to train on their new helicopter, the Sikorsky HRS-1. Except for the commanding officer, LtCol George Herring, most pilots in the squadron had flown fighters during World War II. In August 1951 the squadron deployed to Korea and attached to the 1st Marine Aircraft Wing (1 MAW), where it operated in the central and the western fronts.