the undzungwa mountains cover an area of 16,131.40 km², the largest of the eastern arc ranges. the highest peak in the range is luhombero at . the mountain range extends generally northeast-southwest. the usangu plain lies to the northwest, drained by the great ruaha river and its tributaries. the great ruaha river separates the udzungwa mountains from the rubeho mountains and uvidunda mountains to the northeast. the kilombero river valley lies to the south and southeast. to the southwest the makambako gap separates the udzungwa mountains from the kipengere range.