The Upper Klamath Basin, defined by the drainage area of the Klamath River above Iron Gate Dam, is a unique transitional area between the Cascade Range to the west and the Basin and Range Province of the northern Great Basin to the southeast. This region extends from the southern Lower Klamath Lake area into the Lost River and Upper Klamath Lake basins. Crustal stretching and block faulting created a topography with characteristics similar to both regions. Almost the entire basin is a graben region, bearing basin and range characteristics, formed by uplifting and subsidence along several north-south faults.