Because of her shallow draft and her combination of heavy guns and a howitzer, she was suited for riverside bombardment and assigned to the Mississippi River area where she operated against forces of the Confederate States of America.
USS Carondelet, an ironclad river gunboat, was built in 1861 by James Eads and Co., St. Louis, Missouri, under contract to the United States Department of War. Carondelet was commissioned January 15, 1862, at Cairo, Illinois, naval Captain Henry A. Walke in command, and reported to Western Flotilla (Army), commanded by naval Flag Officer Andrew Hull Foote.
Between January and October 1862, Carondelet operated almost constantly on river patrol and in the capture of Fort Henry and Fort Donelson in February; the passing of Island No. 10 and the attack on and spiking of the shore batteries below New Madrid, Missouri, in April; the lengthy series of operations against Plum Point Bend, Fort Pillow, and Memphis, Tennessee, from April through June, and the engagement with CSS Arkansas on July 15, during which Carondelet was heavily damaged and suffered 35 casualties.
Transferred to United States Department of the Navy control with the other ships of her flotilla on October 1, 1862, Carondelet continued the rapid pace of her operations, taking part in the unsuccessful Steele's Bayou Expedition in March 1863.
One of those to pass the Vicksburg and Warrenton, Missouri batteries in April 1863, Carondelet took part on April 29 in the five and one-half hour engagement with the batteries at Grand Gulf. She remained on duty off Vicksburg, hurling fire at the city in its long siege from May to July. Without her and her sisters and other naval forces, the great operations on the rivers would not have been possible and the United States victory might not have been won.
From March 7 to May 15, 1864, she sailed with the Red River Expedition, and during operations in support of Union Army movements ashore, took part in the Bell's Mill engagement (part of the Franklin-Nashville Campaign) of December 1864. For the remainder of the war, Carondelet patrolled in the Cumberland River.
In 1873, shortly before she was to be scrapped, a flood swept the Carondelet from her moorings in Gallipolis, Ohio. She then drifted approximately 130 miles down the Ohio River, where she grounded near Manchester, Ohio. Her ultimate fate remained unknown until a May 1982 search operation by the National Underwater and Marine Agency pinpointed the location of the wreckage, two days after a dredge passed directly over the wreckage, demolishing most of the wrecked vessel.