Old Faithful is located in the Upper Geyser Basin, purportedly the world's largest concentration of geysers. Old Faithful is not the only geyser that has a schedule. Several of the other geysers have pre-eruption charactersitics that make it possible to predict their eruption times. Old Faithful is neither the most regular nor the largest in the basin, but it does erupt more frequently than the others.

The eruption of all geysers varies daily in the timing and volume of water. On longer time scales, the variablity in eruptions is caused by seismic activity that changes the geometry of the underground fractures. Information from Old Faithful privides examples of both scales of variability. Old Faithful's eruption interval has typically been on the order of 0.5 to 1.75 hours. Historically, the average has varied between 60-65 minutes in 1870, 65.5 minutes in 1964, 78 minutes in 1990, and 92 minutes in 2004. Following an earthquake located at Borah Peak, Idaho, in 1983, the average interval between eruptions became temporarily longer.