Upper Geyser Basin in Yellowstone National Park has the highest concentration of geysers anywhere in the world. This section of the UNESCO World Heritage-listed park is often overlooked because many people concentrate on Old Faithful, but it’s definitely worth walking through. There are a good number of geyser groups in the basin making for a good few miles of walking. This entry focuses on Geyser Hill, the section nearest to Old Faithful, and describes only a few of the geysers in the area.
Along the path around Old Faithful, there’s an extension that takes you to a bridge over the Firehole River. Crossing the bridge will bring you to Geyser Hill, a loop trail containing several geysers, springs, and pools. When I came to the path, I went counterclockwise and did half the loop before continuing to the Grand and Castle Group.
The first interesting feature I encountered was Infant Geyser. It’s filled with cloudy gray water and doesn’t look like much, but many years ago it was filled with clear water and erupted every so often.
Next, I came to Teakettle Spring. It consists of a raised rim and a spring that doesn’t erupt. Steam constantly rises from the cone, hence the name “Teakettle Spring”.
I continued along the path to Sponge Geyser. It’s named for the sponge-like cone around the vent. Eruptions occur every minute but only reach a height of one to two feet. The water temperature is roughly 199°F.
Across the path is Pump Geyser, which is in a constant state of eruption. The water doesn’t really shoot out, but it sometimes splashes a few feet high. It’s named for the mechanical pumping sound it makes.
Pump Geyser has a temperature of 199°F and the constant flow of water creates a small pool nearby. This pool has a very active community of microbes which attracts mites, flies, and wolf spiders.
Doublet Pool is two springs that have come together to form a pool. It’s made up of beautiful shades of blue. It’s said that if nobody is on the boardwalk, you can feel the pool thumping.
The small Aurum Geyser is next. Named for the golden colors around the vent, it erupts every few hours with heights reaching between 10 and 30 feet. It does have periods of dormancy, but is sometimes active every three hours or so.
Beach Spring was considered a geyser in the early 20th century but hasn’t erupted in many years. It consists of a deep pool with dark blue colors.
Past the trail to Solitary Geyser is Pendant Spring. This spring doesn’t have much action, but it’s nice to look at. It has a mostly white and light blue basin with a small vent in the center. At this spring, I was able to see a crow chase a small mouse right into the water. The mouse died instantly. The crow was trying to retrieve it but the water was too hot.
Across the path, Ear Spring is shaped like an ear and is one of the hottest springs on Geyser Hill with temperatures up to 205°F. It was originally named Oyster Spring in 1890 but tourists later began calling it Devil’s Ear. It’s four feet deep and is in a constant state of boiling.
Continuing around the Geyser Hill loop rather than taking the path to the Grand and Castle Group will bring you to Goggles Spring. It’s lined with yellow and orange cyanobacteria and has a stream of water flowing nearly 400ft to the Firehole River.
Behing Goggles Spring is the Lion Group, which is made up of four interconnected geysers. Lion Geyser is the largest. When it’s active, it erupts every two to five hours with water shooting 30 to 60 feet into the air. The sound before it erupts has been compared to a roaring lion. The other three geysers in the group are named Lioness, Big Cub, and Little Cub.