Type C3-class ships were the third type of cargo ship designed by the United States Maritime Commission (MARCOM) in the late 1930s. As it had done with the Type C1 ships and Type C2 ships, MARCOM circulated preliminary plans for comment. The design presented was not specific to any service or trade route, but was a general purpose ship that could be modified for specific uses. A total of 162 C3 ships were built from 1939 to 1946.

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.