Midwestern Gas Transmission is a 366-mile small pipeline running bidirectionally from Portland, Tennessee to Joliet, Illinois. Owned by ONEOK, Inc. and operated by Midwestern Gas Transmission Company, it functions at more than 50% utilization, primarily serving utility/power and marketer sectors. Significant customers include Tenaska Marketing Ventures, BP Canada Energy Marketing, and Northern Illinois Gas Co. The pipeline system also includes a mainline extension from Portland, Tennessee to Hartsville, Tennessee, transporting gas in both northerly and southerly directions.