The 1,499,013-acre (2,342.208 sq mi; 6,066.29 km2) forest is bordered on the north by British Columbia, on the east by Colville National Forest, on the south by the divide between the Methow and the Stehekin–Lake Chelan valleys, and on the west by North Cascades National Park.

The vegetation varies similarly, from the western boreal forest, to the eastern high-elevation steppe.

Drained by the Waptus River, it is notable for its views of Summit Chief and Bears Breast mountains.

In September 2012, a severe lightning storm ignited hundreds of fires, the largest of which were located southwest of the city of Wenatchee and east of Blewett Pass.

[6] A lightning strike near Jolly Mountain on August 11, 2017, ultimately burned more than 38,000 acres and forced significant evacuations.

The forest's initial area of 1,732,820 acres (701,250 ha) extended from the northern Okanogan River near the Canada–United States border to divide the Lake Chelan and Entiat watersheds to the southern Cascade Crest.

[8] The United States Congress designated almost 65 percent of the forest's area as the Lake Chelan-Sawtooth Wilderness under the National Wilderness Preservation System around 1984, upon land formerly occupied by the former Chelan Division of the Washington Forest Reserve.

[citation needed] On October 15, 2024 a U.S. Navy EA-18G Growler crashed east of Mt.

Rainer, causing closures in the Pear Butte region of the Natches Ranger District from October 21 - December 31 as the military searched for debris relate to the incident.