Here's a book written by Dr Joe Medicine Crow - last War Chief of the Crow Nation.

https://www.thriftbooks.com/w/from-the-heart-of-the-crow-country-the-crow-indians-own-stories_joseph-medicine-crow/607760/#edition=4808650&idiq=6026173

He wrote many books on Crow culture and history but a lot of them aren't published anymore.

ETA: I am Crow. And iirc, we don't have origins out of Yellowstone National Park. The beginning of our people start with two Chiefs who lived to the east among many lakes and forests. Both chiefs received visions from the Great Spirit, and a pod of seeds. One was told to plant the seeds to provide sustenance for their people. The other - Chief No Vitals - was to go west and plant the seeds in the mountains they find. No Vitals did not leave immediately, but when he was in middle afe. He and the people who went west became the Crow but they didn't have a name originally. They wandered for 100 years before they settled in Crow Country. The went as far west as the great Salt Lake, as far south as north New Mexico, and finally settled in southern Montana/northern Wyoming. No Vitals was dead by then, but his protege Running Coyote was entrusted with the seeds to the mountains, named by Chief Medicine Crow as "the Beartooths, the Wind River Mountains, the Crazy Mountains, the Absarokas, and the Grand Tetons".

"The Crow country is a good country. The Great Spirit has put it exactly in the right place; while you are in it you fare well; whenever you go out of it, whichever way you travel, you will fare worse." - Chief Arapooish to Mr Robert Campbell of the Rocky Mountain Fur Company.

Also, just wanted to say, according to Dr Medicine Crows book, some French brothers ventured from their Canadian Outpost and came across us and named us Beaux Hommes. Because we are some damn good looking people. 😎