Telltale signs of geologic activity surround Grover Hot Springs State Park. Bold granite peaks to the northwest are the work of immense mountain building forces. Old lava flows cover hundreds of square miles to the east, giving the Markleeville area its distinctly volcanic appearance. Ice Age glaciers carved this valley into the rugged form that visitors admire today.
The hot-springs here are a by-product of similar processes - the interplay of rock and fire and ice. Water melted from winter snow seeps deep into the earth's crust, where it comes into contact with hot rock. Heated to the boiling point, the water then percolates to the surface along a zone of weakness - a fault - which cuts across this valley. When the water emerges from the ground at a temperature of 148 degrees, it contains a variety of dissolved minerals, but little of the foul-smelling sulfur often associated with thermal springs.
For more than a century tourists have enjoyed these springs, but humans are not the only visitors here. Minerals precipitated by the cooling water create a natural salt lick, attracting deer and other wildlife. Eventually the water flows across the meadow to join Hot Springs Creek; some, evaporating, will return to the mountains as rain or snow and so begin the journey again.