History 

Tailcodes 

History 

HMM-561 was activated on 31. January 1967, to provide refresher training to UH-34 Sea Horse pilots and crews heading to Vietnam. The squadron, based at MCAF Santa Ana, fell under the command of Marine Aircraft Group 56 and the 3rd Marine Aircraft Wing. Undermanned from the start, the unit remained in cadre status until 9 May 1968 when they were formally stood up. In addition to training, the squadron's mission also included conducting local Search and Rescue missions, providing VIP transport, and other commitments as required by local commands.

Starting in January 1969, UH-34 deployments started to slow down as the Marine Corps transitioned its remaining squadrons to the CH-46 Sea Knight. The squadron was decommissioned on 27. October 1969 and was the last active UH-34 squadron in the Fleet Marine Force. Squadron members were absorbed by the other helicopter communities or given the Marine Air Reserve Training Detachment (MARTD) of their choice as a next duty station.

The squadron was reactivated as VMM-561 on 2 December 2010, after 18 months as a cadre unit. VMM-561 was deactivated on 6. July 2012 and replaced at MCAS Miramar by VMM-363.