Description - Mt. Jefferson is the dominant feature of this High Cascades area, along with Three Fingered Jack (7,841'). Mt. Jefferson's slopes are mantled by five glaciers: Whitewater, Waldo, Milk Creek, Russell, and Jefferson Park. Other geographic features include steep talus slopes, rock outcrops, and alpine meadows. There are over 150 lakes. Total Area: 111,177 acres. Elevation: 3,000 ft to 10,497 ft.
- Vegetation is predominantly Douglas-fir, silver fir, sub-alpine fir, mountain hemlock, lodgepole pine, ponderosa pine, several species of cedar as well as species like vine maple, huckleberry and rhododendron.
Recreation - There are 190 miles of trails, including a 40 mile stretch of the Pacific Crest National Scenic Trail.
High-Use Areas: Jefferson Park, Eight Lakes Basin, Marion Lake, Pamelia Lake, Jack Lake, Duffy Lake, and Santiam Lake.
Climate - With its huge elevation range, climate on the Deschutes changes drastically depending on elevation. The high elevations receive much more precipitation and colder temperatures. Much of the precipitation comes from October to April, mostly in the form of snow in the higher elevations. Winter temperatures can drop below zero degrees Fahrenheit. Late spring, summer and early autumn tend to bring clear, sunny days, with warm to hot temperatures at the low elevations and moderate temperatures at the higher elevations. Summer afternoon thunderstorms are not uncommon.
The Mt. Jefferson Wilderness is located at the northern end of the Deschutes National Forest and the northeast end of the Willamette National Forest, to the northwest of Sisters, Oregon. The most popular entry points are Pacific Crest National Scenic Trail #2000 and Summit Trail #4041 from Highway 20 at the south end; Marion Lake Trail #3436 off Road 2255; Pamelia Lake Trail #3439 off Road 2246, 13 miles southeast of Detroit; Pacific Crest National Scenic Trail #2000 from Breitenbush Lake in the north; Duffy Lake Trail #3427, off Road 2267. Popular east side entry points are Cabot Lake Trail #3437 and Road 1234 at Jack Lake; Jefferson Lake Trail #4001, from Road 1292; Whitewater Trail #3429, off Road 2243.