The Unadilla class was a class of gunboat built for the Union Navy at the outbreak of the American Civil War. Ships of the class were also known as "90-day gunboats" due to their rapid construction. The class was designed to be fully oceangoing while having a light enough draft to be able to operate close inshore, for blockade duty or other operations in shallow waters. The Unadilla class was sold off quickly by the Navy at the end of the war, most of them going into merchant service. Little is known about their subsequent careers.