Dominating views in the northern portions of the Reserve is 2,333 foot Monument Peak. Immediately south of Monument Peak, the Reserve lands dramatically change. Here Dawson Canyon cuts deeply into the western edge of the Gavilan Plateau forming exceedingly steep and rugged canyons. Still further south lies the hulking mound of Estelle Mnt., which at 2,767 feet, is the highest point in the Reserve. The flanks of Estelle Mnt. are similarly cut deeply by rocky canyons and gorges, many of which support nesting birds of prey.
Reserve is surprisingly diverse.
Several additional sensitive species occur on the Reserve at some time during the year. In total about 40 species considered sensitive are found on the Reserve. Herpetiles are very abundant on the Reserve. Birds are especially plentiful in the Reserve. Lake Mathews serves as a major stopping-off spot along the Pacific Flyway, and ducks and other migrants abound.