Grotto Geyser located in the administrative territorial entity Wyoming
History
On September 18, 1870 members of the Washburn-Langford-Doane Expedition entered the Upper Geyser Basin where in a day and a half of exploration, they named seven geysers of which Grotto was one. Nathaniel P. Langford described the Grotto in his 1871 Scribner's account:
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