Marine Medium Tiltrotor Squadron 166 (VMM-166) is a United States Marine Corps tiltrotor squadron consisting of MV-22 Osprey transport aircraft. The squadron, known as the "SeaElk", is based at Marine Corps Air Station Miramar, California. Activated in 1985, HMM-166 was the youngest CH-46 helicopter squadron in the Marine Corps. The squadron was redesignated as a tiltrotor squadron on June 23, 2010.