USS Monongahela (AO-178) was a Cimarron-class fleet replenishment oiler commissioned in the United States Navy from 1981 to 1999.

Ships of this class were built with a mast that folded at the AN/SPS-55 pedestal platform to allow the passage under the Huey P. Long Bridge.

During her service life the ship has traveled to many parts of the world, including: The Mediterranean Sea, the Indian Ocean, the North Atlantic, the Pacific Ocean and the Caribbean Sea.

The Monongahela was decommissioned and stricken from the Navy list on 30 September 1999, and berthed at the James River Reserve Fleet, Fort Eustis, Virginia, awaiting final disposal.

Her classification was changed on 24 May 2005 as a possible candidate for Foreign Military Sales to Chile.