Midway Geyser Basin is much smaller than the other basins found alongside the Firehole River. Despite its small size, it contains two large features, the 60 by 90 m (200 by 300 feet) wide Excelsior Geyser which pours over 15,000 L (4,000 U.S. gallons) per minute into the Firehole River. The largest hot spring in Yellowstone, the 110 m (370 feet) wide and 37 m (121 feet) deep Grand Prismatic Spring is also found here.