MV Mark W. Barker is a large diesel-powered lake freighter owned and operated by the Interlake Steamship Company. She is the first of the River-class freighters constructed for an American shipping company. MV Mark W. Barker is the first ship on the Great Lakes to be powered with engines that meet EPA Tier 4 standards. It is the first U.S.-flagged, Jones Act-compliant ship built on the Great Lakes since 1983.

Lake freighters, or lakers, are bulk carrier vessels operating on the Great Lakes of North America. These vessels are traditionally called boats, although classified as ships. Freighters typically have a long, narrow hull, a raised pilothouse, and the engine located at the rear of the ship.