ORGANIZATION

6 Months Ended

Jun. 30, 2011

ORGANIZATION

ORGANIZATION

NOTE 1        ORGANIZATION

TC PipeLines, LP and its subsidiaries are collectively referred to herein as “the Partnership.” In this report, references to “we,” “us” or “our” refer to the Partnership.

The Partnership owns the following interests in natural gas pipeline systems:

·   a 46.45 percent general partner interest in Great Lakes Gas Transmission Partnership (Great Lakes);

·   a 50 percent general partner interest in Northern Border Pipeline Company (Northern Border);

·   a 25 percent interest in Gas Transmission Northwest LLC (GTN), a Delaware limited liability company. GTN owns a 1,353-mile pipeline that transports natural gas from the British Columbia, Canada/Idaho border to a point at the Oregon/California border;

·   a 25 percent interest in Bison Pipeline LLC (Bison), a Delaware limited liability company. Bison owns a 303-mile pipeline that transports natural gas from the Powder River Basin in Wyoming to Northern Border’s pipeline system in North Dakota;

·   a 100 percent interest in North Baja Pipeline, LLC (North Baja); and

·   a 100 percent interest in Tuscarora Gas Transmission Company (Tuscarora).

The Partnership is managed by its General Partner, TC PipeLines GP, Inc. In addition to its aggregate two percent general partner interest in the Partnership, the General Partner owns 5,797,106 common units, together with its general partner interest, representing an effective 12.6 percent interest in the Partnership at June 30, 2011. TransCanada Corporation also indirectly holds an additional 11,287,725 common units representing a 20.7 percent limited partner interest in the Partnership at June 30, 2011.