Sikorsky, the manufacturer of UH-34, originally developed Seahorse for the Navy but the Army would become a primary user as well using the name “Choctaw”. The U. S. Army employed the UH-34 principally for general utility purposes, as well as VIP transport flights, and SAR missions. The UH-34 played a major role for the Navy in anti-submarine warfare along with search and rescue duties. In the Vietnam War, the Marine Corps depended on Seahorse reliability and modified the UH-34 into one of the first gunship helicopters of the war. The Armys Choctaw helicopter successfully carried out numerous missions in Vietnam ranging from combat assault to medical evacuation and general cargo transportation. The UH-34 was also the final evolution of large piston-engine helicopters before the rise of turbine powered designs. Ultimately the UH-34 was flown by all branches of the U. S. military and also by the armed forces of Argentina, Belgium, Brazil, Cambodia, Canada, Chile, Costa Rica, France, Germany, Haiti, Indonesia, Israel, Italy, Japan, Katanga, Laos, Netherlands, Nicaragua, Philippines, Soviet Union, Thailand, United Kingdom, Uruguay, and Vietnam.
The Sikorsky UH-34D variant of the Seahorse, used for assault missions, was a 12-seater military helicopter mainly used by the U.S Navy. The US Marine Corps ordered the HUS-1 Seahorse (UH-34D) version on October 15, 1954. This helicopter entered Marine service on March 31, 1961, and served in units at New River, North Carolina; Jacksonville; Santa Ana and El Toro, California; and New Orleans. On November 25, 1970, it was retired and placed in storage at Davis-Monthan Air Force Base, Arizona, having accumulated 3,416 flying hours.