Wis. Stat. § 198.02: District, creation, powers.

A municipal power district may be created as provided in this chapter and when so created shall be considered a municipal corporation and may exercise the powers granted in this chapter. Any 2 or more municipalities, whether contiguous or otherwise or in the same or different counties, may organize and incorporate as a municipal power district. No municipality may be divided in the formation of a municipal power district, and no municipality shall be included in a municipal power district unless approved by a majority of the votes cast in that municipality at an election under s. 198.06 on the proposition of whether a district should be created.