The ship was long overall, had a beam of and had a maximum draft of . Oneota had a tonnage of 1,034 tons burthen and displaced . Her crew consisted of 100 officers and enlisted men. Oneota was powered by a two-cylinder horizontal vibrating-lever steam engine that drove one propeller using steam generated by two Stimers horizontal fire-tube boilers. The engine gave the ship a top speed of . She carried of coal. Oneota's main armament consisted of two smoothbore, muzzle-loading, Dahlgren guns mounted in a single gun turret. Each gun weighed approximately . They could fire a shell up to a range of at an elevation of +7°.