Atomizer Geyser is a cone geyser in the Upper Geyser Basin (Old Faithful area) of Yellowstone National Park in the United States. Atomizer Geyser is part of the Old Road Group which includes Artemisia Geyser, a short distance down the Firehole River from Old Faithful and other major Upper Basin geysers. The geyser is named for a fine mist resembling the spray from an atomizer that is ejected during major eruptions.