The first USS St. Mary's was a Galley in the United States Navy.

One of seven galleys constructed and equipped by the Navy for operation under the War Department on coast defense duty during the Quasi-War with France, St. Mary's officers were appointed by the Secretary of the Navy, while the remainder of her crew was composed of local recruits.

St. Mary's cruised off the Georgia coast from 1798 to 1801 to protect local commerce and coastal settlements from armed French vessels operating in the area.

Able to maneuver under oars in the absence of wind, the galley was ideally suited for the defense of the many inlets and small harbors along the coast of the southern United States.

In addition to defending settlements and waterways, her duty was to prevent hostile raids, depredations and to take or destroy any armed French vessels encountered.