USS Fort Jackson, a 1850-ton (burden) wooden side-wheel cruiser, was built at New York City in 1862 as the civilian steamship Union. The U.S. Navy purchased her in July 1863 and, after conversion to a warship, placed her in commission as USS Fort Jackson in August of that year. A boiler casualty kept her out of combat service until late in 1863, when she joined the North Atlantic Blockading Squadron. During the next year, Fort Jackson worked to enforce the blockade of the Confederate Atlantic coast. While performing this duty, she assisted in destroying the blockade runner Bendigo (3 January 1864) and captured the steamers Thistle (4 June), Boston (8 July) and Wando (21 October 1864).

In December 1864 and January 1865, Fort Jackson participated in the operations that finally captured Fort Fisher, North Carolina, thus ending blockade running into the port of Wilmington. She was transferred to the West Gulf Blockading Squadron in February 1865 and served off Texas until after the final surrender of Confederate positions there in June. USS Fort Jackson was decommissioned and sold in August 1865. She subsequently became commercial steamer North America and was not broken up until 1879.