“where warm waters halt”
This seems to be the most important clue by virtue of being first. If you get this wrong, your journey might leave you in the cold, but your effort will still be worth the pictures, fun, and memories.
Lots of possibilities. Just check out the other Thrill of the Chase blogs. My thoughts immediately landed on the geysers and hot springs in Yellowstone Park. Once I got the map out, I saw how numerous those hot spots were. And then, there was all the chatter about the Firehole, not something I’d ever heard of.
If you go with hot springs, you soon realize they are found in several other Rocky Mountain states. And you’ll probably find canyons next to most of them……
Then, if you take “halt” to the dictionary, you’ll find a few other meanings. Check it out. This can lead you to places away from water.
If you dive into some history books, you might find an utterly unique idea for “where warm waters halt”ed. I did.