The Spokesman-Review reported Wednesday that Twin Falls, Kootenai, Owyhee and Teton counties, as well as several cities, signed onto the case in Idaho Supreme Court.
Twin Falls County argues a map that splits it into three separate districts puts voters at an unconstitutional disadvantage.
Meanwhile, Kootenai County opposes a district lumping 5,000 of its residents in with voters who live far to the south, in distant Idaho County.
Idaho convened two redistricting commissions this year.
Now, the map that resulted must pass muster with the state’s high court justices before voters learn whether these legislative boundaries will remain come May’s primary elections. (AP)