Ethan Allen was built in 1859 at Boston, Massachusetts; purchased by the Navy 23 August 1861; and commissioned 3 October 1861, Acting Volunteer Lieutenant W. B. Eaton in command. During her first wartime cruise, 27 October 1861 to 30 March 1863, Ethan Allen patrolled in the Gulf of Mexico, capturing eight prizes, and destroying extensive salt works along the Florida coast, thus hampering the Confederate war effort and civilian economy. She arrived at Portsmouth, New Hampshire, 5 June 1865, and was decommissioned there 26 June 1865, and sold 20 July 1865.