Grand Prismatic Spring, in the Midway Geyser Basin beside the Firehole River, is the largest hot spring in the United States: about 370 feet (113 m) across and more than 120 feet deep. Its centre is a startling blue; around it, rings of orange, yellow and green are mats of heat-loving microbes, each colour living at a different temperature as the water cools towards the edge.
There are two ways to see it and you should do both. The boardwalk through Midway Geyser Basin takes you right to its edge, where the steam often hides the colours. The Grand Prismatic Overlook Trail, from the Fairy Falls trailhead a mile south, climbs to a platform on the hillside with the view you have seen in photographs. Many guided tours include a stop here.
What to see at Grand Prismatic Spring & Midway Geyser Basin
Walk the Midway Geyser Basin boardwalk
From the parking area a bridge crosses the Firehole River, where hot water from the basin pours down the bank in coloured streams. The boardwalk loop, under a mile long, passes the steaming crater of Excelsior Geyser — now a huge hot spring that discharges thousands of gallons a minute into the river — then circles past Grand Prismatic and Turquoise Pool. Hold on to your hat: the wind blows hats into the springs every summer.
Climb to the Grand Prismatic Overlook
Park at the Fairy Falls trailhead, about a mile south of Midway. Follow the flat old road along the river, then turn up the signed spur to the overlook platform. The round trip is around 1.2 miles (2 km) with a modest climb; it is the single best viewpoint in the geyser country. Late morning and early afternoon on a sunny day, when the steam is thinner, give the strongest colours.
Continue to Fairy Falls
If you have more time, carry on past the overlook spur through young lodgepole forest to Fairy Falls, a slender waterfall of about 200 feet (60 m). The round trip from the trailhead is about 5 miles (8 km) and mostly flat. This is bear country: carry bear spray and make noise.
Fountain Paint Pot and Firehole Lake Drive
A few minutes north, the Lower Geyser Basin has the bubbling mud of Fountain Paint Pot and the one-way Firehole Lake Drive past Great Fountain Geyser. Together with Midway they make an easy half-day between Madison and Old Faithful.
Getting to Grand Prismatic Spring & Midway Geyser Basin
- Location: on the Grand Loop Road between Madison Junction and Old Faithful, about 8 miles (13 km) north of Old Faithful.
- From West Yellowstone: about 25 miles; 40–50 minutes.
- Parking: the Midway lot is small and is often full from about 10 am to 4 pm in summer. Rangers sometimes close the entrance when it is full; try early, late, or come back.
- Overlook: park at the Fairy Falls trailhead lot, about 1 mile south of the Midway lot.
Tips before you go
- Cool mornings are the steamiest — wonderful for atmosphere, poor for colour. For colour, go on a warm, sunny day around midday.
- Do the overlook first and the boardwalk second, or the other way round if the overlook lot is full.
- Never step off the boardwalk; the bright mats are hot water with a thin living skin.
- Drones are banned throughout the park — the overlook trail is how you get the view from above.
Tours that visit Grand Prismatic Spring & Midway Geyser Basin
These guided trips include Grand Prismatic Spring & Midway Geyser Basin or pair well with it:
Full-day guided tour from €325 From Jackson: Yellowstone National Park Day Trip with Lunch
A long but complete day from Jackson around Yellowstone’s lower loop: the Old Faithful area, Midway Geyser Basin with Grand Prismatic Spring, Fountain Paint Pot, the canyon and Hayden Valley. The drive through Grand Teton on the way is a bonus. Expect an early start and a late return.
- Old Faithful, Midway Geyser Basin and Fountain Paint Pot
- Canyon area and Hayden Valley
- Lunch included
Small-group day trip from €399 From Bozeman: Express Yellowstone Tour (1 Day)
A small-group day trip from Bozeman covering Fountain Paint Pot, Grand Prismatic Spring, Old Faithful, Yellowstone Lake and Artist Point. Bozeman is a long way from the park, so it is a full 13-hour day — but it solves the problem of not having a car.
- Fountain Paint Pot and Grand Prismatic Spring
- Old Faithful and Yellowstone Lake
- Artist Point and the canyon falls
Small-group day tour from €385 West Yellowstone: Yellowstone Day Tour Including Entry Fee for US Residents
The most-booked day tour from the gateway town closest to the geyser basins, with hundreds of reviews. A guide drives the big sights of the lower loop — Old Faithful, the Grand Canyon of the Yellowstone and the wildlife of Hayden Valley — so you can watch for animals instead of the road. Read the listing for what the entrance fee covers for visitors from abroad.
- Old Faithful, the canyon waterfalls and Hayden Valley
- Park entry included for US residents — check the listing if you are not
- Starts minutes from the West Entrance
Full-day group tour from €329 Yellowstone: Old Faithful, Waterfalls, and Wildlife Day Tour
A full-day group tour from Jackson with a perfect five-star average across hundreds of reviews. It focuses on the three things most people come for — Old Faithful, the Grand Canyon of the Yellowstone and wildlife in Hayden Valley — with the guide spotting animals along the way.
- Old Faithful Geyser
- Grand Canyon of the Yellowstone
- Wildlife viewing in Hayden Valley
