According to the Museum’s website (which also provides technical specifications):

Courtesy of the United States Army

This C-7A was built by de Havilland Canada in 1962 and is one of 159 purchased by the U. S. Army. It saw service in Vietnam and used for cargo and troop transport, and medical evacuation. It is a STOL (short takeoff and landing) airplane designed to be extremely rugged and reliable, and could operate on unimproved landing surfaces of less than 1,000 feet for close support in forward battle areas. The Caribou was a workhorse for the Army and could be configured to carry up over four tons of cargo or vehicles, 32 fully equipped combat troops, or up to 20 patient litters. Rear doors facilitated quick loading and unloading, and could be opened in the air for dropping paratroopers.

This aircraft had been assigned to the Connecticut AVCRAD (Aviation Classification Repair Activity Depot) in Groton. It was flown to Bradley International Airport in September, 1991 and was the last official flight of any C-7 in U. S. military service.

Taken with a Sony RX-100 M3.