NorthWestern Energy, Montana's monopoly utility that has been making headlines lately, is set to merge with another utility, South Dakota-based Black Hills Corp.

The companies announced Tuesday that the boards of directors for both companies unanimously approved an all-stock merger that will create a singular electric and natural gas utility company spanning eight contiguous states — Arkansas, Colorado, Iowa, Kansas, Montana, Nebraska, South Dakota and Wyoming — and serving roughly 2.1 million customers, who mostly use natural gas.

Based on the proposed merger, Black Hills shareholders will own approximately 56% of the combined company, while NorthWestern Energy shareholders will own 44%.

A press release on the deal said the companies were combining "to meet rising energy demand" and

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