The geysers of the Upper Basin
in Yellowstone National Park represent the most concentrated group in the world - over 250 are found in an area just 2 miles across, the majority of those in a narrow band adjacent to the Firehole River
, on both sides but mostly east, arranged in 5 distinct groups starting in the south at Old Faithful and nearby Geyser Hill. Two further clusters are at Black Sand Basin
, alongside Iron Spring Creek, and Biscuit Basin
in the north, which is also along the Firehole River but more separated from the main region.
From the visitor center next to Old Faithful, a wide, asphalt, wheelchair-accessible track runs for 1.5 miles on the west side of the river as far as Morning Glory Pool, the most northerly feature, while lesser paths and boardwalks lead to specific geysers, and form an alternative route on the east side. With an average number of stops it takes about 2 hours to walk to the far end but there is enough to see to last a full day, especially if much time is spent waiting for some of the geysers to erupt.
Map and Geyser TourMap of the Upper Geyser Basin
, showing all roads, trails and named thermal features, 71 of which are linked to detailed description and photograph pages.
Like many of Yellowstone's larger geysers, Old Faithful
was named by the 1870 Washburn Expedition, the first modern day explorers of this region, on account of its regularity, discharging as it does every 45 to 90 minutes to heights of 180 feet, with the interval proportional to the duration of the previous eruption, though this geyser is none of the tallest, most impressive, prettiest or most frequently erupting. But it is definitely the most watched since it is right next to the carpark, the visitor center and Yellowstone Lodge. The geyser is half encircled by a curved, raised viewing area, 300 feet from the vent, allowing up to 2,000 people to see the performance, and the full compliment are often present on busy days in midsummer. Depending on the amount of steam and the wind direction, Old Faithful may be difficult to photograph effectively; the best views are often from above at Observation Point
, 250 feet up and 1/4 mile away in the hills on the far side.
Walking northwards from Old Faithful, the first group is at Geyser Hill
, on the far side of the Firehole River - over 40 geysers are found here, together with other vents and pools, spread over an elevated area that gives good views up and down the valley. A boardwalk loops around the hill and an extension climbs to Observation Point for an even better perspective, continuing on to Solitary Geyser
, a large pool in a clearing in the woods surrounded by colorful mineral deposits. On Geyser Hill, the biggest geysers are twice-daily Beehive
, and Giantess
, which erupts only occasionally. The main opening of Anemone Geyser
is circled by delicate sinter formations and discharges about every 10 minutes to heights of 10 feet, with a second, smaller vent also frequently active. Doublet Pool
has two adjacent springs filled by deep blue waters, surrounded by flat terraces. Other notable features are the Lion Group
, Aurum Geyser
, Pump Geyser
, Sponge Geyser
and Plume Geyser
The other geyser groups receive proportionally fewer visitors the further away they are from the carpark. Next is Castle-Grand; Castle Geyser
has a huge cone that points to it being one of the oldest in the whole basin. It erupts quite dramatically on average every ten hours and is one of five that has estimated times posted at the visitor center, as does Grand Geyser
. This is one of the highlights of the park, reaching heights of 200 feet and producing a great fountain of steam and water lasting for around ten minutes in several bursts, with performances every 7 to 15 hours. Nearby Turban and Vent
geysers are part of the same system, usually spouting before and after the main event. Also near Grand is Spasmodic Geyser
, and as the name suggests, this erupts irregularly to different heights, through several interconnected vents. Two beautiful hot springs in this area are Twilight Spring
and Crested Pool
The Giant-Grotto Group comprises a small collection either side of the Firehole River. Grotto Geyser
is photogenic even when not erupting because of its unusual, multipart cone, though it does discharge forcefully for up to 10 hours, with intervals varying from an hour to two days. Two smaller adjacent geysers, Spa
, are linked to Grotto via underground channels. Giant Geyser
is also most notable for its cone, 12 feet tall, as its eruptions are infrequent and the activity variable, but it can reach heights of 250 feet. The other three main sites are Oblong Geyser
, right on the river bank, which is unusual for the very large volume of water discharged, plus two more large blue pools: Beauty
The Daisy area is a little further away from the Firehole River, west of the main path, and is centered on Daisy Geyser
, another of those with predicted times. This shoots boiling water up to 100 feet at a 70° angle, so on windy days produces a great curtain of whitewater and steam. Intervals between eruptions range from 2 to 4 hours. The cone of Daisy in is the middle of quite a large mineralized plain that also contains the Comet
geysers. Away from these, the land is more wooded and other thermal features are more isolated. One famous pool is 200°F Punch Bowl Spring
, permanently bubbling and encircled by a raised lip of deposited geyserite.
Morning Glory-Riverside Group
The northernmost group on the east side of the Firehole River is Morning Glory-Riverside, based around what could be the prettiest hot spring in all the basin - 23 foot deep Morning Glory Pool
. This has a clear, dark blue center and a green-yellow-brown edge, though its beauty has lessened in recent years owing to debris from thoughtless visitors which has clogged the vent and reduced the temperature and hence the brightness of the colors. Nearby are three linked geysers: Fan
, also adjacent to the river and totalling over ten separate vents which erupt noisly but not predictably, as there could be months or hours between activity. One more large geyser is Riverside
, in a trailless area on the east bank of the Firehole, viewable from a spur path on the west side; this is another of the five predicted geysers, erupting every 6 hours to 75 feet.
Biscuit Basin is a compact area of small geysers and springs, on the west side of the Firehole River near its confluence with Iron Spring Creek. All features can be viewed on a short loop trail; there is Mustard Spring
, a boiling vent enclosed by rocks coated an attractive yellow-brown color by deposited sulphur, and Saphire Pool
, which has particularly clear, bluish water. The main geysers are Shell
(the highest in the basin - up to 30 feet) and Rusty
. From Avoca Spring
at the west edge of the basin, a 1.2 mile trail
leads along the canyon of the Little Firehole River to 70 foot Mystic Falls
Black Sand Basin
There are only five main features at Black Sand Basin, one mile west of Old Faithful, but all are interesting. The basin itself contains patches of fine black sand, eroded from obsidian (volcanic glass), and sits on a bend in Iron Spring Creek, a tributary of the Firehole River. A short spur road and then a boardwalk trail leads first to Opalescent Pool, a calm, dark blue, reflective pond made especially beautiful by the stark color contrast with reddish brown algae mats around the edge and silicified white dead trees just beyond. On the opposite side of the creek is the effervescent Cliff Geyser, that erupts irregularly but noisily from a circular vent just a few inches from the stream and at the same level as the water. The biggest pool in the basin is Sunset Lake, often partly obscured by the steam it produces. Two other pretty springs are Emerald Pool and Rainbow Pool.