Not easy, I just tried to do a simple county breakdown. Too many large counties next to each other along the break line.
And 56 freaking counties to deal with. Maine with 1.3 million and 528 cities and town (Montana has 364) has just 16 counties. I assume Montana school children are not forced to learn all of the county names.
Just be sure to call it mar county and not meager county.
In the horse and buggy era, a county seat was not supposed to be more than two days to get to, preferably one. So the maximum dimension of a county should be less than 50 miles. They stretched it out West, as it was.
Texas has 254 counties.
Texas is 1.8 times as large as Montana.
By that metric, Montana should have 141 counties instead of only 56.
Wisconsin has 72 counties. It is 1/5 the size of Texas.
By the Wisconsin metric, Montana should have 198 counties.