Idaho is a state in the Pacific Northwest of the United States. The capital is Boise, which is also the largest city having about 190,000 inhabitants.
The state is part of the northern Rocky Mountains, the geology is mostly volcanic. Southern Idaho, an area of 60,000 km² or 35% of the state is covered with lava. This is the largest unbroken field of lava on the North American Continent. During 30 Million years of eruptions up to 1,500 m of lava was deposited. There are impressive volcanism related National Parks, like Yellowstone Park and Craters of the Moon National Monument. Many relevant caves are of volcanic origin, especially lava tubes, but there are also karst caves.
The state also has some mining activities, but only few tourist mines. The complex geology in an orogenic area results in a great variety of natural resources. However, the most important resource is gold.