USS Cairo is one of the first American ironclad warships built at the beginning of the U.S. Civil War. Cairo is the lead ship of the City-class gunboats and named for Cairo, Illinois. In June 1862, she captured the Confederate garrison of Fort Pillow on the Mississippi, enabling Union forces to occupy Memphis. As part of the Yazoo Pass Expedition, she was sunk on 12 December 1862, while clearing mines for the attack on Haines Bluff. Cairo was the first ship ever to be sunk by a mine remotely detonated by hand. The remains of Cairo can be viewed at Vicksburg National Military Park with a museum of its weapons and naval stores. Service in the American Civil War Cairo was built by James Eads and Co., Mound City, Illinois, in 1861, under contract to the United States Department of War. She was commissioned as part of the Union Army's Western Gunboat Flotilla, which had US Navy Lieutenant James M. Prichett in command. Cairo served with the Army's Western Gunboat Flotilla on the Mississippi and Ohio Rivers, and their tributaries until she was transferred to the Navy on 1 October 1862, with the other river gunboats. She was commanded by Flag Officer Andrew Hull Foote. Active in the occupation of Clarksville, Tennessee, 17 February 1862, and of Nashville, Tennessee, 25 February, Cairo stood down the river on 12 April, escorting mortar boats to begin the lengthy operations against Fort Pillow. An engagement with Confederate gunboats at Plum Point Bend on 11 May, marked a series of blockading and bombardment activities which culminated into the abandonment of the fort by its defenders on 4 June. On 6 June 1862, two days later, Cairo joined in the triumph of seven Union ships and a tug over eight Confederate gunboats off Memphis. Five of the opposing gunboats were sunk or run ashore during this action; two were seriously damaged, and one managed to escape. That night, Union forces occupied the city. Cairo returned to patrol on the Mississippi until 21 November, when she joined the Yazoo Pass Expedition. On 12 December 1862, while clearing mines from the river, preparatory to the attack on Haines Bluff, Cairo struck a "torpedo" (or naval mine) detonated by volunteers hidden behind the river bank and sank in 12 minutes. There were no casualties. Armament Like many of the Mississippi theatre ironclads, Cairo had her armament changed over