Like the northern extent of the Oregon Cascades, the southern half has even less rugged of a profile when compared to the Washington end of the Cascade Mountains, but still has an equitable density of waterfalls throughout. The Southern Oregon Cascades region consists of land from the Row River basin south to the California border, and west from the Interstate 5 corridor to the Deschutes River and Highway 97.
Undoubtedly the primary geologic feature of the southern cascades is Crater Lake â€“ the massive remnant of the explosive history of Mount Mazama, once Oregonâ€™s tallest mountain. Radiating out from the Mazama volcanic group is evidence of widespread volcanism that has produced some of the largest, most scenic and most impressive waterfalls in southern Oregon. But not only has this violent past resulted in the base geology to produce waterfalls, but the porous bedrock has allowed hundreds of springs and aquafirs to burst forth from the ground, ensuring even flow in many of the regionâ€™s largest rivers for most of the year. Some of these springs even gush out of the ground forming waterfalls immediately as they emerge. Fortunately this landscape is sufficiently isolated from major cities such that the majority of the region is undeveloped (logging aside) despite the fact that only a fraction of the land is actually federally protected.