Geothermal areas of Yellowstone#Upper Geyser Basin

The upper Geyser Basin (English: Upper Geyser Basin ), also called Old Faithful region is the region in Yellowstone National Park, which has the highest concentration of geothermal objects in the park. It is located on the edge of Yellowstone Caldera in Wyoming, south of the town Norris, and comprises about 2.5 km ² of land. Among the geothermal objects located around a quarter of all the world's existing geysers, including Old Faithful, Grand Geyser, Riverside Geyser, Castle Geyser, Aurum Geyser and Daisy Geyser. It is drained into the Firehole River.

The hills surrounding the upper Geyser Basin, are remnants of acidic lava from the Quaternary (Pleistocene ).

Glacial deposits ( moraines ) of the last ice age created under the Geyser Basin storage areas for water. Only thanks to these memories geysers are possible.

Evidence of strong erosion in the Upper Geyser Basin ubiquitous - of drainage channels that are cut into the sinter to the drainage of the Firehole River. South of the Old Faithful form mountains. There the Rocky Mountains reach a height of 2518 m and divide the country into two watersheds.