Upper Geyser Basin in Yellowstone National Park has the highest concentration of geysers in the world. A variety of thermal features exist in this 2 square mile area - geysers, hot springs and fumaroles. Upper Geyser Basin is home to the world's most famous geyser - Old Faithful. It also features other impressive predictable geysers - Grand, Castle, Daisy and Riverside geysers.
Numerous thermal features sprinkled across Upper Geyser Basin are accessible by flat paved and boardwalk trails. There are multiple trails suitable for short or extended hikes beginning at Old faithful area and run along the Firehole River. One can easily spend a day exploring the entire basin or minimum half a day to check out the main attractions. Some of the most popular trails are - Up to Morning Glory Pool 1.1 mile one way; short side trail to Daisy and Punch Bowl; loop around Old Faithful 0.6 miles.
There are many large and small, prominent and unnamed geysers across the basin. These are some of the features that can be easily spotted from the boardwalk.
Old Faithful Geyser:
Old Faithful is the world's most famous geyser and the first to come to mind when you think of Yellowstone. Its highly predictable eruptions and its eruption heights are what makes this a crowd favorite. Old Faithful's vent is in the center of a massive geyserite mound. It erupts every 1-1.5 hours, its eruptions can reach between 100-200 feet and last 1-5 minutes.
Castle Geyser exhibits a massive 12 feet tall, 120 feet circumference and 20 feet diameter geyserite cone, the largest cone in yellowstone. Castle Geyser erupts at an interval of approximately 12 hours, shoots water up to 100 feet high for 20 minutes, followed by loud and long steam phases.
Tortoise Shell Spring:
Located at the base of Castle Geyser on the northwest side, it is a constantly boiling spring.
This hot spring is located a little south of Castle Geyser.
Among more than 10,000 hot springs scattered across Yellowstone, only few are as intensely colored as Crested Pool. Crested Pool is a beautiful blue superheated pool, constantly boiling bubbling and overflowing. Every few minutes it boils heavily reaching few inches to few feet high, rarely reaches even 10 feet.
Deleted Teakettle Geyser:
Also on the banks of Firehole River, this geyser continues splashing 1-2 feet high every few minutes.
Scalloped Spring is a hot spring on the bank of Firehole River with a colorful run-off channel.
Churn geyser has occasional eruptions up to 15 feet high.
Belgian Pool is a very quiet colorful pool with no eruptions or overflowing activity. The pool was named for a Belgian tourist, who in 1929, accidently fell in and died.
Grand Geyser is another spectacular attraction at Upper Geyser Basin. It is located at a distance from the boardwalk and is surrounded by six other smaller geysers. Grand Geyser is one of the geysers whose eruption times are predicted by the national park. It erupts in a grand manner and with great force. Its erupts in 5 or more hour intervals, in 6 bursts each lasting several minutes, and can reach up to 180 feet high.
West Triplet Geyser:
Weat Triplet Geyser is part of Grand Geyser Complex and is the closest to the boardwalk. It has irrugular eruptions up to 10 feet high.
Economic geyser is a round hot spring with thick orange-brown bacteria mats around its wall. It has been an active geyser in the past but has remained dormant for many decades.
Wave Spring is similar to Economic Geyser is appearance and activity.
Beauty Pool is one of the prettiest and colorful pools in Upper Basin. Beauty Pool and Chormatic Pool are connected underground and they alternate activity. Although the only activity is overflow, one pool overflows for months while the other lays low, and then they switch.
Read Beauty Pool for acitivty information. And usually the pool that overflows has the prettiest colors.
Inkwell Springs on the riverbanks, are a collection of spouters named for the dark color run-off channels.
Oblong Geyser, named for the shape of its crater, is surrounded by elaborate sinter formations. Its eruptions are unpredictable, but when it does erupt it shoots large amounts of water up 20-40 feet high.
Giant Geyser is the second tallest geyser in the world, first being Steamboat Geyser in Norris Geyser Basin. Giant Geyser is a cone type geyser with impressive eruptions, although irregular and unpredictable. An eruption can reach 250 feet tall, lasts over an hour and produces millions of gallons of water.
Mastiff Geyser is located close to Giant Geyser. It has frequent boiling and splashing eruptions up to 5 feet tall. Mastiff Geyser plays a significant role in predicting Giant Geyser's eruptions. Its pool fill up with water during Giant's hot periods, and if the water level stay up it indicates a possible eruption.
Catfish Geyser erupts frequently up to 10 feet tall. During hot periods, it joins Mastiff and Giant Geysers and erupts for several minutes up to 75 feet tall.
It is an 8 feet tall unusually shaped geyser. Its unique shape is a result of sinter formations on old tree trunks. Grotto Geyser erupts at intervals of 6-8 hours reaching up to 30 feet tall and lasts for hours.
Spa Geyser is an irregular geyser. It usually fills and overflows during Grotto's activity and has widesly spaced eruptions anywhere between 3 feet to 45 feet tall.
Riverside Geyser sits on the bank of Firehole river. It is another predictable geyser in Yellowstone. It erupts regularly at an interval of 5.5-7 hours. The water starts to rise and overflow about one to two hours before an eruption, followed by boiling and splashing minutes before and then the actual eruption of up to 75 feet tall.
Mortar Geyser and Fan Geyser:
Mortar and Fan Geysers have several vents, nearly a dozen. Their eruptions are irregular, have long intervals of several days or can even stay dormant for months. But when they do erupt, they start off with explosive power. Fan Geyser's main vent is the largest, shoots at an angle up to 125 feet high, and Mortar Geyser can reach above 80 feet.
Morning Glory Pool:
Morning Glory is one of the popular thermal features at Yellowstone. Early visitors threw coins and garbage into the pool eventually clogging its vent which resulted in lowering the temperature. Lower temperature gave way to the growth of orange-brown bacteria around its rim which in turn affected the appearance of center blue color that now appears green. Although some of the debris was cleared, the vent is blocked deep down and any attempts to induce eruptions have failed.
Daisy Geyser is one of the most famous and predictable geyser at Upper Geyser Basin. With average intervals between 85-100 minutes, its two cones start with spashes few minutes before, erupt at a 70 degree angle and reach up to 75 feet tall.
Punch Bowl Spring:
Punch Bowl Spring is named for the bowl shaped raised crater rim formed by sinter deposits. Sinter deposits build up very slowly, on average 1-2 inches every 100 years. Its activity has remained constant for the past 100 years, water boiling and bubbling within its rim. Green and orange bacteria growth can be seen in its run-off channel.
Sawmill Geyser has frequent activity and its geyserite surrounded crater can drain completely between eruptions. It gurgles and quickly fills up indicating a pending eruption and shoots water up to 30 feet high.
Tardy Geyser is surrounded by small to medium sized geyserite. It can erupt up to 10-20 feet high.
Liberty Pool is a quiet and dirty looking pool. It has low temperatures and light steaming is the only activity observed.
Bronze Spring is normally a quiet pool. When it is active it can erupt 1-2 feet sometimes up to 15 feet tall.
North Goggles Geyser:
It is a cone shaped geyser with irregular eruptions. Its activity starts with rise of water level, followed by bubbling, overflowing and finally erupting. It mostly has minor eruptions less than 10 feet tall and can reach 20-50 feet during major eruptions.
Shaped like a human ear, it is a contantly boiling spring. Any heavy eruption or heavy boiling is linked to the activity of nearby geysers.
Pendant Spring, named for its shape, has been dormant for decades. It is surrounded by sinter deposits and has some microbial growth on its run-off channel.
Beach Spring is a bowl shaped pool with geyserite deposits surrounding its vent. The water in the pool rises and falls within minutes.
Aurum Geyser is named for the golden color sinter surrounding its vent. It is an active geyser with eruptions every 3-4 hours reaching 10-15 feet high.
Geyser Hill Area:
Silica in the run-off waters from many geysers in the Geyser Hill group have deposited to form beautiful small terraces which can be seen on both sides of the boardwalk. Orange-brown bacteria have grown on these terraces presenting a colorful display.
Doublet Pool is two hot springs together with a geyserite ledge on its surface. The pool produces an inaudible thumping which can be felt from the boardwalk when no one is walking by. The thumping is caused by steaming bubbles collapsing deep within the pool. It has had minor eruptions in the past but currently only overflows very small amount of water.
Sponge Geyser is one of the smallest geysers named for its rounded sponge like appearance. It is active and erupts frequently, almost every minute, and consists mostly of boiling with small eruptions reaching only few inches high.
Pump Geyser erupts almost continuosly, no acitivty changes have been noticed since its discovery. It is a small geyser named for its pumping sounds. It splashes 2-3 feet high and produces steady flow of water which has resulted in the growth of microbial community in its run-off channels.
Vault Geyser's activity is connected to nearby Giantess Geyser. It erupts up to 20 feet high during Giantess eruptions.
Infant Geyser used to be a crystal clear alkaline geyser. Over the years water chemistry changed to acidic, causing a muddy grey appearance and Infant geyser no longer showed eruptions.
Big and Little Anemone Geysers:
Both vents are surrounded by small to medium sized geyserite. Both have frequent eruptions. Big Anemone erupts every 10 mintues, water quickly fills up its crater and erupts for 25-45 seconds, up to 6-8 feet high. Little Anemone has smaller eruptions but lasts much longer.