🇺🇸 USA · Thermopolis, Wyoming
♨ Temperature
54°C
⛰ Altitude
1393 m
⚗ pH
—
💧 TDS
—
🌊 Flow rate
—
📅 Established
—
✓ Verified on 2026-07-24
Hot Springs State Park in Thermopolis, Wyoming, is home to Big Spring — reputedly the world's largest mineral hot spring — which discharges over 8,000 litres per minute at a constant 54°C. By state law, a portion of the water must always be available to the public at no charge, a tradition dating to the Shoshone and Arapaho treaty of 1896. The free state bath house offers both indoor mineral pools and outdoor soaking, drawing visitors who come to experience naturally hot, sulfur-tinged water in the heart of Wyoming's high desert.