 The Central Oregon region covers approximately , and sits at the convergence of the Basin and Range, Cascades, Blue Mountains, and Columbia River Plateau geologic regions.Because it is part of a historically volcanic region, volcanic rock formations are a common sight, including lava beds, volcanic buttes, crater lakes, volcanic plugs, and lava tubes.Consequently, Deschutes is the most cave-rich county in Oregon with over 500 lava tubes.