Horizon Lines, Inc. operates as a holding company for Horizon Lines, LLC and other wholly owned subsidiaries Horizon Lines of Alaska, LLC (Horizon Lines of Alaska), Horizon Logistics, LLC (Horizon Logistics), Horizon Lines of Puerto Rico, Inc. (HLPR), Hawaii Stevedores, Inc. (HSI), Road Raiders Transportation, Inc. and Road Raiders Logistics, Inc. The Company is a domestic ocean shipping company and the ocean cargo carrier serving all three noncontiguous domestic markets of Alaska, Hawaii and Puerto Rico from the continental United States. Horizon Lines operates as a Jones Act container shipping business with primary service to ports within the continental United States, Alaska, Hawaii, and Puerto Rico and also offers terminal services. HLPR operates as an agent for Horizon Lines in Puerto Rico and also provides terminal services in Puerto Rico. The Company provides certain inland transportation services via its Road Raiders Transportation subsidiary.