Yellowstone Lake, West Thumb Geyser Basin (Lakeside Cones) & Mud Volcano

Covering 341 square kilometres (132 square miles) with 177 kilometres of shoreline at 2,357 metres (7,733 feet) elevation, Yellowstone Lake is the largest high-elevation lake in North America. Its surface stays frozen under up to a metre of ice until late May, while sitting directly over the southern edge of the Yellowstone Caldera, creating a shoreline where boiling geothermal springs erupt right on the beach and underwater.

1. West Thumb Geyser Basin (1.0 km Flat Boardwalk Loop, 30 to 40 Mins)

Located where the South Entrance Road from Grand Teton meets the Grand Loop Road, West Thumb Geyser Basin is a smaller volcanic caldera formed 174,000 years ago that flooded with lake water:

• Abyss Pool & Black Pool: peer down into the 16-metre-deep emerald cone of Abyss Pool and cyan-blue Black Pool, which shifted from dark olive-green when its water temperature rose in 1991.
• Fishing Cone & Lakeshore Geyser: along the beach boardwalk, geyser cones project out of the waves of Yellowstone Lake. In the 1800s, anglers stood on the rim of Fishing Cone, caught cutthroat trout in the icy lake, and swung their fishing line into the boiling cone to cook the fish on the hook, a practice banned long ago.

2. The 1891 Lake Yellowstone Hotel & 'Mud Volcano and Dragon's Mouth Spring'

Driving north along the western shore of Yellowstone Lake toward Hayden Valley, stop at two landmarks:

1. The 1891 Lake Yellowstone Hotel: step into the bright yellow Colonial-Revival sunroom of the oldest hotel in Yellowstone, order a drink and sit by the picture windows listening to a string quartet while watching waves roll toward the Absaroka Mountains.
2. Mud Volcano & Dragon's Mouth Spring (12 km North of Fishing Bridge): walk 5 minutes to Dragon's Mouth Spring, where surging waves of boiling, acidic water slam inside a rock cavern with a booming roar and belch clouds of steam.