USS Patapsco was a Passaic-class ironclad monitor in the United States Navy during the American Civil War.

Assigned to the South Atlantic Blockading Squadron, she took part in a bombardment of Fort McAllister on 3 March.

On 7 April, Patapsco joined eight other ironclads in a vigorous attack on Fort Sumter, and received 47 hits from Confederate gunfire during that day.

In November 1863, Patapsco tested a large obstruction-clearing explosive device that had been devised by John Ericsson.

On 15 January 1865, while participating in obstruction clearance operations in Charleston Harbor, Patapsco struck a Confederate mine and sank, with 75 lost.