I have caught them around Makoshika park near Sidney MT.
You mean Glendive right? I've seen all kinds of critters in Makoshika but never a scorpion. Mostly little lizards and blue snakes that can haul ass. I believe they are called blue racers?
I saw them as a kid in Glendive playing/riding dirt bikes in Makoshika. We found all kinds of cool shiit out there. Very cool place.