The Interlake Steamship Company is an American freight ship company that operates a fleet on the Great Lakes in North America. It is now part of Interlake Maritime Services.

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.