Oregon has the largest portion of the Great Basin in the Pacific Northwest, encompassing arid desert landscapes.

The Great Basin, a vast region characterized by arid deserts and endorheic basins, covers parts of several western states. In the Pacific Northwest, Oregon holds the largest share, with areas like the southeastern Oregon High Desert and the Alvord Desert falling within the Great Basin's boundaries. This area features unique geology, sparse vegetation, and diverse wildlife adapted to the dry climate. While states like Idaho and Washington touch the Great Basin slightly, Oregon’s portion is more extensive, making it an integral part of the state’s ecological and geological makeup.