USS Aroostook, a 691-ton Unadilla class screw steam gunboat built at Kennebunk, Maine, was commissioned in February 1862. In early March she assisted the storm-disabled USS Vermont, suffering damage herself in the process. After repairs, Aroostook arrived at Hampton Roads, Virginia, where she participated in operations against Norfolk and, once that port had fallen, up the James River. She engaged Confederate forces on several occasions, among them the bombardment at Drewry's Bluff on 15 May. In September 1862, after the end of General McClellan's Peninsula Campaign, the gunboat served briefly with the Potomac Flotilla before being ordered to the Gulf of Mexico.

Aroostook joined the blockade of Mobile Bay, Alabama, in October 1862, and served off there for nearly a year, during which time she took part in the capture or destruction of several blockade running sailing vessels. Stationed off the Texas coast from November 1863, she took three more blockade runners and assisted in destroying another. Aroostook left the Gulf in September 1865, some months after the end of the Civil War, and was decommissioned at Philadelphia, Pennsylvania.

Recommissioned in December 1866, Aroostook voyaged to the Far East by way of the Cape of Good Hope, arriving at Hong Kong in August 1867. As a unit of the Asiatic Squadron, she operated off Japan and on anti-piracy patrols along the China coast. USS Aroostook was decommissioned at Hong Kong in September 1869 and sold a month later.