Bison beside boiling ground in Yellowstone

The image that defined my first Yellowstone day was a bison standing beside active thermal ground, close enough to steaming pools and bubbling mud that wildlife and geology stopped looking like separate attractions. They simply occupied the same landscape.

I had arrived from Worland after Cloud Peak and entered through Yellowstone's East Entrance. The first surprise was administrative rather than geological: on my 2026 visit, the seven-day vehicle pass cost $35, and as a non-US resident aged 16 or over I also faced the new $100 nonresident fee. I had no problem paying the normal park entrance fee, but the separate surcharge felt unnecessarily unwelcoming. It was not the most graceful introduction to the world's first national park.

Once through the gate, irritation had serious competition. The road opened towards Yellowstone Lake, a sheet of blue water large enough to reset my sense of the park's scale. A later river stop added fast water and dense conifer forest before the scenery began to behave much less normally.

Bison in the Wyoming sauna

At the Mud Volcano area, the wildlife and geothermal halves of Yellowstone stopped pretending to be separate. Grey pools churned, ochre water ran through pale ground, and bison stood close to the active features as if this were an ordinary place to spend the afternoon.

An American bison (Bison bison) is impressive even in a meadow. Beside boiling ground it becomes almost absurdly photogenic. One animal was close enough for a tight portrait; another later walked alone across the steaming flats. My explanation was simple: it was heating up in a natural Wyoming sauna.

Yellowstone's bison matter beyond the photographs. This is the only place in the lower 48 states where a bison population has remained continuously free-ranging since prehistoric times. Their survival gives the encounter a significance that a roadside wildlife stop would not normally have.

The mud itself was a small chemistry lesson. Yellowstone's mudpots form where water is limited and acidic conditions break surrounding rock down into clay. Hydrogen sulfide contributes the familiar rotten-egg odour, while steam and gas turn the wet clay into a surface that bubbles, folds and collapses.

Why Hayden Valley stays open

The landscape then widened into water, meadow and long green curves. Hayden Valley looked calm after the Mud Volcano area, but its openness also has a geological explanation. Fine lake sediments and glacial deposits created clay-rich soils that drain poorly. Meadows can therefore outcompete trees across much of the valley, producing precisely the wet grassland favoured by bison.

The bison photographs changed with the landscape: one animal beside the car, two grazing in bright green vegetation, others dispersed across open grassland, and finally a small group above pale ground. The connection between geology and wildlife was no longer abstract. Old lake sediments helped make the meadow; the meadow supported the herd.

An afternoon of unfinished ground

By mid-afternoon the animals had largely disappeared from the photographs and the surface itself became the subject. A turquoise pool sat below a forested ridge; elsewhere steam moved among dead trees and small blue openings punctured pale mineral ground.

The strongest impression was not one famous feature but the number of variations. Dark water met orange edges, fallen branches lay across mineral crust, and steam repeatedly hid and revealed the flats.

The coloured surfaces were almost abstract at close range, but the wide basin views restored their context. Yellowstone's caldera is not experienced as one tidy crater rim. From the road it reveals itself gradually through hours of hot ground, vents, pools and landscapes that keep changing character.

The day still had more steam and more mud. A pale ridge carried several vents, a hot pool produced a dense white cloud, and the final mudpots rose in slow circular bubbles before collapsing back into grey clay.

Toward evening, forest and mountain ridges returned between the active areas. One final red slope was still steaming, but the practical problem had become accommodation. After a whole day of stops, short walks and sights, I continued north to Livingston. Rooms closer to Yellowstone were roughly $300-500; there I found a perfectly good motel for about $60. The cheap night in Montana also positioned me for the next morning's return through the North Entrance.

That first Yellowstone day on the US trip never settled into one category. A bison stood beside boiling ground, with wildlife and geothermal activity occupying the same landscape as if neither needed to explain the other.

From Wisconsin to Pikes Peak, from 12 centimetres to 4,302 metres