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                                                                      EXHIBIT 21
 
                         SUBSIDIARIES OF THE REGISTRANT
                               SEPTEMBER 30, 1997
 
Parent of Bay State Gas Company -- None
 
Subsidiaries of Registrant -- Northern Utilities, Inc.
                     -- Granite State Gas Transmission, Inc.
 
Subsidiaries of Granite State Gas Transmission, Inc. -- Natural Gas Development,
                                                     Inc.
                                         -- Bay State Energy Enterprises, Inc.
                                         -- EnergyUSA, Inc.
                                         -- EnergyEXPRESS, Inc.
                                         -- LNG Development Corp.
 
     Each subsidiary is wholly owned. Northern Utilities, Inc. and Granite State
Gas Transmission, Inc. are incorporated in the State of New Hampshire. Bay State
Energy Enterprises, Inc., EnergyUSA, Inc., EnergyEXPRESS, Inc., LNG Development
Corp., and Natural Gas Development, Inc. are incorporated in the Commonwealth of
Massachusetts.
 
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