Upper Geyser Basin, Main South Area
The Upper Geyser Basin is considered the main attraction for most visitors. This massive thermal area contains hundreds of thermal features, including world famous Old Faithful. It is located at the end of the road reached by taking the Old Faithful Interchange. We split this geyser basin into two sections, the area south and east of the footbridge over the Firehole River near Castle Geyser, and the area north and west of the bridge. This is the southern section, starting from the Old Faithful viewing area.
Old Faithful is the most well known geyser in the world. There is a massive seating area wrapping around it, and that area will likely be full come eruption time. The interval is currently about 92 minutes, and the next expected eruption time is always posted in several areas. It shoots as high as 180 feet and can last one to five minutes.
Go right of Old Faithful and cross the Firehole River. Take the first left on the boardwalk and head towards Beehive Geyser. This geyser erupts up to 180 feet for four or five minutes. Its eruptions are uncommon though, occurring only once or twice a day at irregular intervals. We were lucky enough to see it erupting, albeit from a distance, as shown to the left.
Shortly beyond Beehive Geyser is Heart Spring. This pool’s shape vaguely resembles a heart. It is a deep and very hot spring.
Lion Geyser Group
The Lion Geyser Group is located at the next boardwalk intersection. It consists of four geysers, the largest of which is called Lion Geyser. We caught it in eruption in the photo to the left.
The boardwalk heads north for a while, and arrives at an intersection. Straight ahead is the North End of Upper Geyser Basin. To the left is a bridge over the Firehole River, leading to features below. To the right is Spasmodic Geyser. This geyser erupts nearly constantly from 20 different vents, sometimes increasing up to 10 feet high.
Cross the bridge and quickly come to the Crested Pool. This pool is extremely hot, resulting in its clear blue color. It sometimes bubbles over to heights of up to eight feet.
The boardwalk joins a paved trail. Castle Geyser is located here. This popular geyser has one of the largest cones of any geyser in the world. It currently erupts about every 13 hours to heights of 75 feet. It frequently splashes out of its cone, as seen at left.