The second USS Grampus was a side-wheel steamer in the United States Navy.

Originally named Ion, she was purchased by Rear Admiral David D. Porter for the U.S. Navy on 22 July 1863, at Cincinnati, Ohio, for US$9750.

By 14 November 1863, with Acting Master Elijah Sells in command, she was recognized as a "nice little receiving vessel in first-rate order," but contained no furnishings or weapons other than ten cutlasses and revolvers.

Litherbury in command, Grampus remained at Cincinnati, Ohio, assisting in stripping of ships for conversion to gunboats, and effecting their delivery to fleet staging points for the Mississippi Squadron, principally Cairo, Illinois, and Mound City, Illinois.

This article about a specific ship related to the American Civil War is a stub.