USS Catoctin (AGC-5) was an Appalachian-class amphibious force flagship in the United States Navy during World War II.

Converted to a combined operations and communications headquarters ship, Catoctin was recommissioned 24 January 1944 and reported to Atlantic Fleet.

From her antennas flashed the commands which controlled the activities of thousands of men, in ships, landing craft, and airplanes, ashore, afloat, and aloft.

On 11 February, she welcomed President Franklin D. Roosevelt and his party, including Fleet Admiral William D. Leahy, for an overnight stay.

The command ship embarked military passengers at Oran, and proceeded to Philadelphia, where she underwent overhaul, followed by refresher training.

During October and most of November, Catoctin was headquarters for negotiations with the Chinese Communists, in power in Shandong and Manchuria, in which attempts were made to allow the officially recognized Nationalist Government to reestablish itself.