Sour Lake

Acidic lake sustained by sulfur-oxidizing microbes; perched water system within a caldera setting; part of one of the world’s largest volcanic systems

Microbial ecosystems in extreme acidity; sulfur cycle; caldera hydrothermal dynamics

Enter Yellowstone via any main gateway; drive to Mud Volcano area; park at Mud Volcano Trailhead; follow the Mud Volcano Trail boardwalk looping Sour Lake.

Mud Volcano Trailhead

Mud Volcano Trail loop; connections to other thermal areas along the loop

Sour Lake overlook along the Mud Volcano Trail boardwalk; keep distance from vents

Early morning steam with soft light; close-ups of vent rims; long shot over the boardwalk

Overlooks along the boardwalk; steam plumes framed by nearby vents

Mammals like bison, elk, bears, wolves frequent Hayden Valley nearby

Mornings can hold fog; heat and steam can distort air; summer thunderstorms common

Mud Volcano area; other thermal features; Yellowstone Caldera region

Interpretive signs; vault toilets; limited water at trailheads

Boardwalks with variable gradient; consult signs for accessibility at Sour Lake section

Boardwalks limit risk; hold hands near edges; hot water hazards

Interpretive signs; vault toilets at Mud Volcano area; no on-site drinking water