Dry and Wonderful (Until It Wasn't)
The September project weekend never quite happened. Three weeks after the weeklong, most of us were still unpacking, still catching up on …
Been underground in Montana or Wyoming?
Write it up for the grotto. Every report adds to a record going back to 2011 — and the photographs are how the caves get documented.
Recent trips
The grotto's field record, newest first.
Two Caves Enter, One Cave Leaves
Since 2021 the Bighorn–Horsethief project has run on weekends: drive up Friday, cave all weekend, drive home tired. This August, for the …
Montan-oh-maybe, and the Cave Everybody Walked Past
Every caver with a copy of Caves of Montana has done this at least once. You read a description written decades ago …
Thirteen Feet from Glory (Give or Take a Hundred)
Every project weekend has a story the map tells afterward. June's was a cliffhanger. It started with a plan that sounded almost …
Three Thousand Feet and an Empty Trauma Room
If April was the weekend that got snowed on, Memorial Day was the weekend where everything went right, at least underground. Above …
Two Phones, Three Distos, Three Brothers
The 2026 season at Bighorn–Horsethief opened the way every sensible caving season should, with a snowstorm. Three inches fell in Bozeman, more …
Who we are
A scattered, stubborn caving community
Chartered in 2000, our purpose is to promote the discovery, exploration, scientific study, and conservation of caves and karst. Our core is in Montana, but our membership stretches across Idaho, Wyoming, Washington, Utah, Texas, California, and into Canada.
We survey, inventory, map, photograph, monitor and recreate in caves throughout the Northern Rockies — and a fair amount further afield. We're spread out, but we've kept things active and together for over a quarter-century.
The Bighorn/Horsethief Project
Our flagship long-term survey project, running multiple weekend trips every year plus a week-long summer expedition. Open to members at all experience levels.
What you get as a member
Twelve dollars a year gets you deep into the Northern Rockies caving community — and its records.
334 trip reports
A searchable archive of where members have been caving — with photos, maps and field notes going back years.
Member directory
Find other cavers in your area, contact trip leaders, and plan your next underground weekend.
Small grant program
The grotto funds member projects — from survey equipment to conservation work. Apply anytime.
The cave catalogue
361 Montana and Wyoming caves, with 43 issues of The Darkside in the newsletter archive alongside them.
What's coming up
Meetings, trips and training.
Nothing on the calendar yet.
The grotto's in a bit of a rebuilding phase, and that's where you come in. Host a pub night in your town (we'll help you get it going), share a cave trip you've got in mind, or post a work weekend, a talk, or anything else other cavers might want to join.
Join the grotto to post your own, or sign in if you're already a member. Want help getting a pub night going? Get in touch.
News
The New nrmg.org Is Live. Go Put Yourself on the Map.
On October 22 the grotto's website moved house. The old WordPress site, which spent its last few years held together with plugins, …
Carl Froslie Is the Grotto's New President
At the grotto meeting on July 22, Carl Froslie took over as president of the Northern Rocky Mountain Grotto. If you have …
Newell Campbell's History of Montana Caving — now live on the site
In June 2017, Newell Campbell mailed a manuscript to Hans Bodenhamer: a decade-by-decade history of Montana caving stretching from 1912 up through …