- The Saddle Mountains consists of an upfolded anticline ridge of basalt in Grant County of central Washington state. The ridge, reaching to 2,700 feet, terminates in the east south of Othello, Washington near the foot of the Drumheller Channels. It continues to the west where it is broken at Sentinel Gap (a water gap through which the Columbia River passes) before ending in the foothills of the Cascade Mountains.