USS Ottawa was a Unadilla-class gunboat built for the Union Navy during the American Civil War.

Ottawa joined the South Atlantic Blockading Squadron for service in the waters of the Carolinas, Georgia, and Florida.

During the Civil War she participated in nineteen operations against ships and shore installations from Hilton Head, South Carolina, to the St. Johns River in Florida.

Ottawa returned north and was decommissioned on 12 August 1865 at the New York Navy Yard where she was sold at auction on 25 October for $13,200.

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