USS Moose was a steamer purchased by the Union Navy during the American Civil War. She was used by the Union Navy as a gunboat assigned to patrol Confederate waterways to prevent the South from trading with other countries. Moose, a wooden sternwheel steam gunboat built at Cincinnati, Ohio, in 1863 as Florence Miller II, was purchased at Cincinnati 20 May 1863, and commissioned immediately, Comdr. LeRoy Fitch in command.