Sulphur Spring (also known as Crater Hills Geyser), is a geyser in the Hayden Valley region of Yellowstone National Park in the United States. Sulphur spring has a vent Temperature of 89 °C (192 °F) although the actual temperature of the spring is 79.8 °C (175.6 °F). It is located in the Crater Hills area of Hayden Valley about 1 mile (1.6 km) west of the Grand Loop Road.