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Mountain States Transmission Intertie (MSTI)

NorthWestern Energy (NorthWestern), 40 East Broadway, Butte, MT 59701, has submitted a Montana Major Facility Siting Act (MSFA) application to the Montana Department of Environmental Quality (DEQ) to construct a 500 kV electric transmission line.  NorthWestern proposes to construct, operate, and maintain the line from Montana to Idaho.  As proposed, the line would extend from a new substation approximately 5 miles south of Townsend, MT through the Whitehall and Butte areas to an enlarged Mill Creek substation east of Anaconda and then south along the Interstate 15 corridor in Montana to the Midpoint Substation in south central Idaho.



Winter 2011 Newsletter

Fall 2009 Newsletter



  • Zone 1 - Townsend to Mill Creek
  • Zone 2 - Mill Creek to Glen
  • Zone 3 - Glen to Stateline
  • Zone 4 - Stateline to Sheep Station
  • Zone 5 - Sheep Station to Coffee Point
  • Zone 6 - Coffee Point to Midpoint

Interactive Map with Resource Information
Updated Information shown here is NorthWestern Energy's preferred alignment application and agency developed alternatives. 

NorthWestern Energy's MSTI Project Overview

Supplemental request considering Mill Creek Substation

For additional information please contact Craig Jones at 406-444-0514.