TC PipeLines, LP (TC PipeLines) is engaged in the transportation of natural gas from the Western Canada Sedimentary Basin (WCSB) to a variety of downstream markets. The Company’s portfolio of interstate natural gas pipeline investments in the United States includes a 100% general partner interest in Tuscarora Gas Transmission Company (Tuscarora), a 46.45% general partner interest in Great Lakes Gas Transmission Limited Partnership (Great Lakes), and a 50% general partner interest in Northern Border Pipeline Company (Northern Border). In August 2008, Northern Border sold its wholly owned subsidiary, Bison Pipeline LLC to TransCanada PipeLine USA Ltd., a wholly-owned subsidiary of TransCanada Corporation (TransCanada). In July 2009, the Company acquired North Baja Pipeline, LLC from TransCanada Corporation.