USS Dumbarton was a captured steam operated gunboat acquired by the Union Navy from the prize court during the American Civil War.

She was used by the Navy to patrol navigable waterways of the Confederacy to prevent the South from trading with other countries.

Thistle—a sidewheel steamer—was captured by Fort Jackson on 4 June 1864 while running the blockade off the coast of North Carolina; sent to Boston, Massachusetts, for condemnation; purchased from the prize court on 20 July 1864; renamed Dumbarton; and commissioned on 13 August 1864, Acting Volunteer Lieutenant H. Brown in command.

After being at Norfolk Navy Yard, Dumbarton served as flagship of Rear Admiral W. Radford in the James River, Virginia from 17 February-27 March 1865.

This article incorporates text from the public domain Dictionary of American Naval Fighting Ships.