Distance: 0.8 miles (loop)
Best time of year: Year-round
Last hiked: 2015 September
The West Thumb Geyser Basin is an easy walk around some very colorful hot springs set against the dramatic backdrop of Yellowstone Lake. If you’re coming in from the South Entrance, it’s a great way to acquaint yourself with some of the features that you’ll be seeing much more of.
The trail makes a loop and neither direction is any harder than the other. If you head right, you’re first brought past the Thumb Paint Pots, a small collection of mudpots, where the water is acidic enough to gradually eat away at the ground around it. This causes the pools to have a murky and muddy appearance to them.
From here you can fork to the left or right. Continuing to the right (from your initial direction), the trail descends past the colorful Bluebell Pool on its way down to the lake’s shore. Along the lake’s shore, you see the outline of the entire West Thumb of Yellowstone Lake. This is actually a caldera rim leftover from an eruption that occurred 125,000 years ago. Eventually, when the eruption settled, the 4,000 foot ice sheet on top of Yellowstone Lake in the last ice age joined the caldera to the current Yellowstone Lake. Though a very large eruption, it pales in comparison to the significantly larger eruptions that took place 640,000, 1.3 million, and 2.2 million years ago in this area.
The boardwalk follow the lake’s shore, bringing you past Lakeshore Geyser, Fishing Cone, and Big Cone. Fishing Cone in particular is famous for being the site where people would catch fish in the lake, then drop their line into the geyser to cook it. Of course that’s highly illegal now given how much destruction the early visitors wrought on Yellowstone’s features.
Continuing around the loop, the boardwalk brings you past two impressively colorful hot springs: Black Pool and Abyss Pool. Each has its own spectacular qualities that could distract anyone for quite a while. Off in the distance from those two is also King Geyser. Eruption times can vary so if it’s not going off as you walk by, patience may not reward you here.
The trail continues back up toward where you started, but you have the option of either taking the higher route above the geyser basin and some mudpots closer by, or you can take the lower route which will rejoin the trail back up at the Thumb Paint Pots. Along the latter route are some colorful hot springs. Of course you could always just do both as well.
From Old Faithful, head onto the main highway and head south. Proceed over Craig Pass continuing south for 18 miles until you reach the West Thumb Junction. Take a left and after just a quarter of mile look for the entrance to the parking area on your right. The trail begins at the other side of the parking area from the entrance.