Robert Chambers Reamer (1873–1938) was an American architect, most noted for the Old Faithful Inn in Yellowstone National Park. A number of his works are listed on the National Register of Historic Places for their architecture.

The Old Faithful Inn is a hotel in the western United States with a view of the Old Faithful Geyser, located in Yellowstone National Park, Wyoming. The Inn has a multi-story log lobby, flanked by long frame wings containing guest rooms. In the western portion of the park, it sits at an approximate elevation of 7,350 feet (2,240 m) above sea level.