USS Monadnock was one of four Miantonomoh-class monitors built for the United States Navy during the American Civil War. Commissioned in late 1864, she participated in the First in December and Second Battles of Fort Fisher in January 1865. The ship was later assigned to the James River Flotilla on the approaches to the Confederate capitol of Richmond, Virginia and then sailed to Spanish Cuba to intercept the Confederate ironclad CSS Stonewall.