Exhibit 21.1

                        SUBSIDIARIES OF THE REGISTRANT


1.   The Registrant holds a 98.9899% limited partner interest in TC PipeLines
     Intermediate Limited Partnership.

2.   Through its interest in TC PipeLines Intermediate Limited Partnership,
     the Registrant holds a 30% general partner interest in Northern Border
     Pipeline Company.

3.   The Registrant holds a 98.9899% limited partner interest in TC Tuscarora
     Intermediate Limited Partnership.

4.   Through its interest in TC Tuscarora Intermediate Limited Partnership,
     the Registrant holds a 49% general partner interest in Tuscarora Gas
     Transmission Company.