Fly Geyser is a geothermal geyser located on private land in the Black Rock Desert of Nevada, USA. It was accidentally created in the 1960s during the drilling of a well for geothermal energy. The well was not properly capped and minerals and geothermally heated water began to rise from the hole, forming the unique geological feature that is the Fly Geyser.

The geyser is known for its vibrant and colorful appearance, which is due to the presence of thermophilic algae that thrive in the high temperatures and mineral-rich waters. The geyser continuously spouts water, which is propelled up to 5 feet in the air, and the minerals that are carried in the water have built up over time, forming the multi-colored cone-shaped formation that is visible today.

The Fly Geyser is not open to the public, but visitors can view it from a distance at nearby viewing areas. The geyser is also visible from the air, and aerial tours of the Black Rock Desert are available. The area around Fly Geyser is considered a sensitive ecosystem, and visitors are encouraged to be respectful of the environment and avoid disturbing the local flora and fauna.