I can't stress enough the importance of arriving early at Yellowstone since, as of my visit in the summer of 2024, there are no reservation requirements, and the traffic near the entrance gates and main attractions is horrendous. Inside the park geysers and hot springs abound, and free-roaming bison are a regular sight. Be prepare for all seasons because the weather can change rapidly. It snowed in mid-June while I was there.
The trail to this overlook also leads to Fairy Falls.
To really see the scale of the Grand Prismatic Spring you have to look at it from the Grand Prismatic Overlook Trail, a short and relatively flat 1.2 mile round trip hike that shares a trailhead with Fairy Falls. It's also possible to walk directly over the spring along a short boardwalk of about 0.8 miles. This is the largest hot spring in the United States and my favorite thing I saw in the park.
Snowy weather in June..
The Old Faithful geyser is a short walk from the visitor center parking lot. It erupts about every hour and a half and lasts 5 minutes or less so you might have to wait a while to see it. Inside the visitor center there's a clock that predicts the next eruption time. There's a few gift stores and places for food in the area while you wait.
The Silex Spring is directly opposite the Fountain Paint Pot.
A short stroll along a boardwalk will take you to the Fountain Paint Pot, a spring filled with boiling mud. There's some regular hot springs and geysers as well. The largest regularly erupting geyser here is the Fountain Geyser, reaching heights of 50 feet and lasting for 20 minutes.
Parking is sparse along this one way road.
Firehole Falls is a 40 foot waterfall that can be seen along Firehole Canyon Drive and is one of the first stops inside the west entrance gate. The parking lot is small so make sure to arrive early. There's also a swimming area along this road two miles south of Madison Junction.
It smells like sulphur.
Fountain Flat Drive is more of an access road than an attraction in itself, but there's still some hot springs along the road here. The road eventually dead ends at a parking lot and trailhead for the Sentinel Meadows & Queen’s Laundry Trail, the Ojo Caliente Spring, and a lengthy extension of the Fairy Falls trail leading through open meadow.
Located west of Grand Teton National Park, this national forest is full of mountains, canyons, rivers and rolling foothills.
Upper Mesa Falls.
While not technically inside Yellowstone at all, I thought Mesa Falls was interesting enough to check out if you're staying nearby. It's about an hour outside the West Entrance at Yellowstone. Upper Mesa Falls is accessible from a boardwalk a short distance from the Mesa Falls visitor center, and Lower Mesa Falls can be seen from the Grandview Overlook along the Mesa Falls Scenic Byway road.