Solitary Geyser

Solitary Geyser is a small fountain geyser on the hillside above Old Faithful, away from the dense cluster of thermal features around the main boardwalks. Take the short uphill detour if you want another stop without waiting for a major eruption: it usually goes off every 4–8 minutes, in bursts under six feet that last about a minute. It is a modest show, but you may see several eruptions during one visit. Visitors often describe this as a quieter stop than the central boardwalks.

This was once Solitary Spring, a hot spring that did not erupt. In 1914, a bathhouse diverted its water to swimming pools nearly half a mile away. Lowering the spring’s water level started its eruptions. The pool was removed in 1951, but the geyser kept erupting after the water level recovered.

The clear blue pool sits inside a pale mineral rim. Shallow shelves and runoff channels carry orange and yellow mats of heat-loving microbes; the water averages about 183°F. For a photo, include some of the orange runoff beside the blue pool so the color still reads between bursts. Keep to boardwalks and designated trails: hydrothermal water can cause severe burns, and don’t disturb the fragile mats.

From the Old Faithful Visitor Education Center, follow the boardwalk counter-clockwise about 0.3 mile to the Geyser Hill sign, then continue past the Firehole River bridge to the trailhead. Solitary Geyser is a short uphill detour. If you’re doing Observation Point, continuing west to the geyser and returning down Geyser Hill adds 0.9 mile to the 1.6-mile round trip. The trail is listed as year-round; pets aren’t allowed.