Great Lakes Maritime Heritage Assessment Act of 2014 - Requires the Under Secretary for Oceans and Atmosphere of the Department of Commerce to assess and report on the cultural and historic resources in the waters of the Great Lakes. Directs the Under Secretary to make recommendations in the report on whether: (1) underwater geographic areas in the Great Lakes should be designated as national marine sanctuaries to protect resources of historical and archeological significance; and (2) the designation of a network of underwater Great Lakes areas that protect those resources could bring significant educational opportunities, economic development, jobs, and tourism to the Great Lakes region.