Hot Creek Geologic Site, Mammoth, CA
- Tim Mayhew
- Apr 26
- 2 min read
Hot Creek Geologic Site is a can’t-miss, high-desert detour- located a short distance off Highway 395 near Mammoth, CA, this is where the massive Long Valley Caldera—a dormant supervolcano—reminds you it is very much still active.
How many years did I ride up and down Highway 395 and not know this site was tucked behind the Mammoth Airport? Likely 20-plus years. Then I saw a photo of it on the cover of a magazine and thought, "Where is that?" I had ridden right by it countless times. Well, nuts.
Hot Creek is easy to miss; you wouldn't know it was there unless someone told you. As you reach the open parking lot near the creek, the landscape shifts from high-desert scrub to a brilliant, lush green along the creek. Turquoise pools of boiling water bubble up from the earth, and plumes of steam sometimes rise against the backdrop of the Mount Morrison skyline.
In years past, this was a popular swimming hole, but the site now serves as a sobering lesson in geology. Because of the unstable nature of the magma chamber beneath the hot creek site, water temperatures can spike hundreds of degrees in seconds. Today, it is a "look but don't touch" destination—perfect for a quick photo break off the main highway.
You can access the site via Hot Creek Hatchery Rd. It is paved for the first 2 miles, followed by 3 miles of gravel. A magma chamber sitting 3 miles below the surface powers this boiling creek. Groundwater percolates deep underground, becomes superheated and pressurized, and then rises back to the surface. Hot Creek is also known for "geysering," where water occasionally shoots as high as six feet into the air.
This activity can be intermittent and unpredictable, sometimes producing an audible "popping" sound. The site has been closed in the past when the area became too geologically active; however, after 2016, the activity settled, and visitors were allowed back to view the springs via a short walking trail. If you’re busy zipping up and down Hwy 395, you’d likely never know this active site is here. Plus, it’s near Benton Crossing Rd, which makes for an awesome high-desert loop when paired with Hwy 120 along Mono Lake.
