Hot Springs

Idaho has the most usable hot springs in the Nation, with about 130 soakable out of 340. The water is hot because it is heated from within the Earth's crust, forcing it up to the surface where pools are developed or form naturally near the outflow. Ninety percent of Idaho's 340 hot springs are the result of leftover energy heating water near fault lines. The energy is leftover from when the North American tectonic plate was pushed west as a result of a meteorite collision in the southeast corner of Oregon more than 17 million years ago. Black basalt currently visible along Interstate 84 between Boise and Idaho Falls is evidence of the collision. The other 10 percent of Idaho's hot springs are from water being heated by active volcanoes.