Type C1 was a designation for cargo ships built for the United States Maritime Commission before and during World War II. Total production was 493 ships built from 1940 to 1945. The first C1 types were the smallest of the three original Maritime Commission designs, meant for shorter routes where high speed and capacity were less important. Only a handful were delivered prior to Pearl Harbor. But many C1-A and C1-B ships were already in the works and were delivered during 1942. Many were converted to military purposes including troop transports during the war.

The United States Maritime Commission (MARCOM) was an independent executive agency of the U.S. federal government that was created by the Merchant Marine Act of 1936, which was passed by Congress on June 29, 1936, and was abolished on May 24, 1950. The commission replaced the United States Shipping Board which had existed since World War I. It was intended to formulate a merchant shipbuilding program to design and build five hundred modern merchant cargo ships to replace the World War I vintage vessels that comprised the bulk of the United States Merchant Marine, and to administer a subsidy system authorized by the Act to offset the cost differential between building in the U.S. and operating ships under the American flag. It also formed the United States Maritime Service for the training of seagoing ship's officers to man the new fleet.