Sight · Yellowstone National Park
Two riverbank geysers share a system; eruptions are a bonus.
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Plan your stop
The highest, rockiest slopes around here are a summer buffet for grizzly bears.
Yellowstone Tour Guide
Parkwolf is a GPS audio tour guide for Yellowstone National Park. As you drive, it chimes in with what’s ahead: hidden gems, upcoming stops, history, geology, and wildlife, right through your car’s speakers.
See the Yellowstone audio tourRecorded for this place
Old Faithful and Upper Geyser Basin“You're approaching the Old Faithful area, and I'd make this more than a stop for one eruption. Check the next predicted window at the Visitor Education Center before you start walking.”
Plays as you drive up to Fan and Mortar Geysers in the Parkwolf Yellowstone Tour Guide.
More stories near here in the app
“First time driving through a national park. We used the Yellowstone tour on grand loop Road and it’s just like having a tour guide in your car with you.”
Guide
Fan and Mortar are two adjoining geysers beside the Firehole River in Upper Geyser Basin. You can see them from the bridge and sidewalk leading north toward Morning Glory Pool. I’d pause as I passed, but I wouldn’t wait for an eruption: the interval can stretch from days to months.
Fan is the smaller cone, with three vents and orange-tinted geyserite colored by thermophiles; its outflow reaches the river. Mortar is the larger sinter cone, with three actively boiling vents. Their underground plumbing changed after they were separate geysers, and now their activity matches most of the time. Fan’s broad, outward spray gave it its name; Mortar was named in 1883 for eruptions likened to mortar discharges. Mortar’s eruptions have broken apart the old cone and formed new vents.
The bridge and northbound sidewalk give you views of the cones beside the Firehole. Include the river in a wider photo to show where the vents sit. Keep to boardwalks and designated trails: hydrothermal water can cause severe burns.
Wildlife
713 sightingsGrizzly BearMost seen around 6 AMSighting map
743 sightingsWolfMost seen around 6 AMSighting map
5,273 sightingsBisonMost seen around 7 AMSighting map
3,258 sightingsElkMost seen around 7 PMSighting map
397 sightingsMooseMost seen around 7 PMSighting map
1,494 sightingsBlack BearMost seen around 7 PMSighting mapSighting maps show where each species has been reported across Yellowstone. Wildlife moves, so no sighting is guaranteed.
Keep exploring
EasyBiscuit Basin Trail0.6 mi · 45 min · 0.9 mi awayA short boardwalk loop through Yellowstone's blue pools and geysers.
EasyBlack Sand Basin Trail0.5 mi · 30 min · 1 mi awayShort boardwalk spurs past colorful hot springs and geysers.
ModerateMystic Falls Trail2.4 mi · 2.5 hr · 1.1 mi awayA creekside forest walk to a 70-foot waterfall.
ModerateObservation Point–Solitary Geyser Loop1.9 mi · 2 hr · 1.1 mi awayA short climb trades switchbacks for Old Faithful from above.
EasyOld Faithful to Morning Glory Pool Trail2.7 mi · 2 hr · 1.2 mi awayA level geyser walk ends at a spring changed by its visitors.
EasyGeyser Hill Loop Trail1.2 mi · 1 hr · 1.2 mi awayCompact boardwalk loop past geysers, vivid springs, and steaming runoff.
ChallengingSummit Lake Trail15.4 mi · 8.5 hr · 1.3 mi awayA long CDT walk to an alpine lake and backcountry hot springs.
ChallengingFairy Creek Trail11.3 mi · 7.5 hr · 1.3 mi awayA long backcountry traverse from geyser views to Imperial Geyser.
Sight · 0.1 mi awayMorning Glory PoolA vivid hot spring at the end of a worthwhile basin walk.
Sight · 0.1 mi awayRiverside GeyserRiverside sends its eruption arcing across the Firehole River.
Sight · 0.2 mi awayGrotto GeyserThat twisted cone is worth a stop even between eruptions.
Sight · 0.3 mi awayGiant GeyserEruptions can top 250 feet, but there’s no showtime to plan around.
Sight · 0.3 mi awayDaisy GeyserA 75-foot geyser can shoot sideways across the basin.
Sight · 0.4 mi awayOblong GeyserAt least 10,000 gallons spill into the Firehole when this pool erupts.
Sight · 0.4 mi awayArtemisia GeyserA deep blue pool that can erupt as a rolling boil.
Sight · 0.5 mi awayBeauty and Chromatic PoolsTwo hot springs with water levels that move in opposite directions.Parkwolf’s Yellowstone ranking
The audio tour guide for the drive, plus offline maps, trails, and wildlife heatmaps for when the signal drops.
