National Natural Landmark Status at Iron Mountain Hot Springs
What National Natural Landmark Status Means for Iron Mountain Hot Springs
Iron Mountain Hot Springs was designated a National Natural Landmark by U.S. Secretary of the Interior Deb Haaland on December 13, 2023. The recognition from the National Park Service honors Iron Mountain Hot Springs as the only known hot springs and cave system of its kind in the Southern Rocky Mountains. Iron Mountain is now one of more than 600 National Natural Landmarks nationwide.
Iron Mountain Hot Springs was founded by the Beckley family, who pursued the designation as part of their long-running commitment to preserving the area's natural resources. Guests can still soak in these nationally recognized geothermal waters, drawn from four natural springs into 16 pools ranging from 98 to 108 degrees Fahrenheit.
What Is a National Natural Landmark?
The National Natural Landmark Program has identified and supported the conservation of the country's most outstanding natural sites since 1962. Landmarks sit on both public and private land, and for private owners like the Beckley family, participation is entirely voluntary.
Sites earn the title based on five criteria: outstanding condition, illustrative character, rarity, diversity, and value to science and education. You can find full program details on the National Natural Landmarks program page.
How Iron Mountain Hot Springs Earned National Natural Landmark Status
Steve and Jeanne Beckley pursued the designation to have this unique geological site formally documented, and the review took years of geological evaluation before it was approved. The honor reflects what's happening beneath the surface — not a marketing claim, but a federal finding.
U.S. Senator Michael Bennet publicly recognized the designation, calling attention to the hot springs as a treasured Colorado landmark and praising the Beckley family's conservation work.
The Geology That Makes It Rare
Over millions of years, the Colorado River cut deeper into Glenwood Canyon, eroding the Leadville Limestone beneath the area and carving the pathways and chambers that shaped this unique underground system. Naturally heated mineral water still rises through those same ancient channels today, feeding four natural springs and carrying 14 naturally occurring minerals — including iron, sulfate, and magnesium — to the surface.
During the review, federal scientists documented eight native cave species and 38 unique bacteria types across the connected cave and spring systems, confirming an underground ecosystem that exists nowhere else on Earth. Many of the geological processes that created it are still active, giving researchers a rare, living window into the past.
How Landmark Status Protects the Springs
Designation doesn't change ownership or day-to-day operations, and guests soak exactly as they always have. What it does add is national recognition, technical conservation support, and access to potential grant opportunities that help protect the site's geology for future generations.
Soaking in a National Natural Landmark
People have gathered on this stretch of river for centuries. The first bathhouse was built here in 1897, and today that history carries a new distinction: a federal designation recognizing the springs as a National Natural Landmark.
The property's 16 geothermal pools, fed by these notable springs, now sit amongst 35 pools along the banks of the Colorado River, with views of Iron Mountain and Mount Sopris.
Iron Mountain Hot Springs is open daily from 9:00 AM to 10:00 PM, excluding planned closures, Thanksgiving Day, Christmas Day, and unforeseen circumstances.
Other Colorado National Natural Landmarks
Colorado is home to more than a dozen National Natural Landmarks, including:
Hanging Lake — Glenwood Canyon, just a short drive from Iron Mountain Hot Springs
Garden of the Gods — Colorado Springs
Roxborough State Park — Douglas County
Spanish Peaks — southern Colorado
Protecting the Springs for the Future: Don't Mine Glenwood
The same fragile limestone groundwater network that makes Iron Mountain Hot Springs geologically significant is currently at risk from a proposed quarry expansion just north of town. Rocky Mountain Industrials (RMI) is seeking Bureau of Land Management approval to more than triple the footprint of its Mid-Continent Limestone Quarry — from about 16 acres to 56 acres — including new blasting and mining several hundred feet upslope, near the unstable cliff left by a 2023 rockslide.
Local officials, the nonprofit Glenwood Springs Citizens' Alliance, and Colorado's congressional delegation have raised concerns that expanded mining could damage the geothermal groundwater network feeding the hot springs, along with local air quality, traffic, and tourism. In response, Senators Michael Bennet and John Hickenlooper and Representative Jeff Hurd introduced the bipartisan Glenwood Hot Springs Protection Act, aimed at stopping the BLM from approving the expansion.
We stand with our community in supporting this effort. If you'd like to help protect the water that feeds these landmark springs, visit loveglenwood.org to learn more and contact your member of Congress about the Glenwood Hot Springs Protection Act.
Book Your Visit
Reserve your soak in a National Natural Landmark on the bank of the Colorado River. Book in minutes. Soak for hours. Feel good for days.