Mammoth Hot Springs Upper Terrace Boardwalk

Overview

The Upper Terrace at Mammoth Hot Springs is a front-row seat to living geology. Boardwalks thread through chalk-white travertine and colorful hot springs—look for Dryad, Canary, Grassy, and Cupid Springs—while the formations shift year to year as vents awaken and go quiet. Unlike most of Yellowstone’s rhyolite-dominated hot spots, Mammoth sits on limestone, so hot water laden with dissolved calcium carbonate rises, degasses, and builds these terraces fast.

Route options and distance

Plan on roughly 1.6–2.2 miles total on the boardwalk network depending on how much you explore; expect steps and some steep grades. Portions are wheelchair-accessible, but other segments include stairs and steeper pitches, and transitions between pavement and boardwalk can require assistance. From the Liberty Cap area to the end of the Palette Spring boardwalk is about 135 yards.

Prefer to mix driving and strolling? The Upper Terrace Drive is a one-way, 1.5-mile loop with multiple short boardwalk stops. Parking is available at the top of the terraces and at pullouts along the loop. Trailers, buses, and motorhomes aren’t allowed; park larger rigs at the entrance and explore on foot. There’s designated accessible parking near the start of the drive and accessible viewing at Orange Spring Mound about 0.7 miles in.

What you’ll see

Up close, you’ll notice the white travertine ledges, delicate pools, and color bands from heat-loving microbes. Activity migrates over time, so some famous spots may be quiet while others are roaring—part of the charm here is embracing the change.

Best time to visit

Go early or late for easier parking and thinner crowds. In winter, the road closes to vehicles and becomes a groomed 1.5-mile ski/snowshoe loop; clockwise tends to feel easier, while counter-clockwise ends with a steeper downhill. Expect icy patches and variable conditions near thermal areas year-round. Always check current conditions before heading out.

Safety and etiquette

Stay on boardwalks and designated trails—thin crust and scalding water can cause severe burns. Supervise children closely. Wildlife is common around Mammoth; keep at least 25 yards from bison and elk and 100 yards from bears and wolves. In winter, stick to groomed routes and boardwalks; don’t shortcut across thermal ground.

Tips

• If time is tight, do the drive-and-stroll approach to sample multiple springs fast.
• Bring water; there are stairs and some steep grades on the boardwalks.
• Accessibility is good in select spots, but full coverage isn’t realistic—plan your stops.