Billings, Montana has some big rock walls. They're called the Rims or the Rimrocks. Here's a video about them.

References/Further Reading:

https://billingsgazette.com/news/loca...
https://en.wikipedia.org/wiki/Luther_...
https://billingsgazette.com/news/loca...
https://billings365.com/the-prehistor...
https://www.kulr8.com/news/a-town-cal...
https://en.wikipedia.org/wiki/Rimrocks
https://therimrocks.weebly.com/
https://billingsgazette.com/news/loca...
https://billingsgazette.com/news/loca...
https://www.onlyinyourstate.com/monta...
http://sites.rootsweb.com/~mtygf/boot...
https://www.mdt.mt.gov/travinfo/docs/...
https://sites.rootsweb.com/~mtygf/cou...
https://books.google.com/books?id=tG2...
https://billingsgazette.com/news/loca...
https://sites.rootsweb.com/~mtygf/cou...
https://billingsgazette.com/news/loca...