Rogue-Umpqua Scenic Byway
United States Forest Service    |   Bureau of Land Management

Traveling the Byway, visitors can experience millions of years of geologic time in just one day.

North Umpqua Geology

Colliding Rivers -Resistant sills of basalt deflect Little River and the North Umpqua River, creating a phenomenon that forces the two rivers into a collision course.

Umpqua Rocks Geologic Area - Eroded remains of volcanic rock have created numerous jagged vertical spires: Old Man Rock, Eagle Rock, and Rattlesnake Rock are along Highway 138 between Eagle Rock and Boulder Flat Campgrounds.

High Cascades Features

Watson Falls - About 750,000 years ago volcanic eruptions produced a hot molten lava flow that filled this valley hundreds of feet deep with basaltic rock. Watson Creek spills over the northern edge of this flow to form Watson Falls.

Toketee Falls - Less than 250,000 years ago, molten lava spewed from a vent and flowed like a river through this valley. Basalt columns were formed as the hot lava cooled. The North Umpqua River drops over these formations.

Mt. Thielsen - This 9,182-foot peak was a fiery volcano over a million years ago. It has endured glacial, wind and water erosion through time.

Pumice deposits - Rivers of pumice ash flowing from Mt. Mazama followed the Upper North Umpqua and Rogue River valleys. Pumice banks and canyons up to 400 feet deep remain in the upper valleys. These deposits can be seen between Boulder Flat Campground and Whitehorse Falls along Highway 138 and between Hamaker and Union Creek on Highway 230.

Diamond Lake - The eruption of Mt. Mazama (Crater Lake) sent flows of pumice and ash into this valley, creating an earthen dam and impounding a new lake - Diamond Lake. Flowing springs and streams fill the 3,000-acre lake.

Crater Rim Viewpoint - Once a towering 12,000 foot volcano, Mt. Mazama violently erupted 7,700 years ago, creating the deepest lake in the United States (1,943 feet deep) - Crater Lake.

Upper Rogue Geologic Sites

Rabbit Ears - This formation may have resulted from a massive volcanic event over seven million years ago. Geologists speculate the unique twin shapes were once part of a large caldera.

Rogue Gorge/Natural Bridge - The Rogue River cuts its way through 1.25-million year old lava flows. The rushing river follows ancient lava tubes, forming natural bridges and gorges.

Table Rocks - Seven million years ago, a river of lava averaging 150 feet deep poured into the ancient Rogue River Valley. The soils of the valley have been slowly eroding away leaving these unique twin mesas 800 feet above the existing valley floor.

Download the Rogue-Umpqua Scenic Byway Brochure

The North Umpqua Segement The High Cascades The Upper Rogue Segment Segment Brochures
Mt. Thielsen Watson Falls Crater Lake Colliding Rivers