Twin Sisters

Twin Sisters spans 13,051 acres in the Colville National Forest of Ferry County, Washington, in the Kettle River Range of the Okanogan Highlands. The roadless area rises through U.S. Mountain, King Mountain, Mack Mountain, and the paired summits of Twin Sisters. The area lies in the North Fork Deadman Creek watershed; King Creek, Camp Creek, Wash Creek, High Bridge Creek, and the North Fork Sherman Creek drain its slopes into Deadman Creek and the upper Columbia drainage.

Forest communities reflect the dry inland gradient of the Kettle River Range. Lower slopes carry Northern Rockies Ponderosa Pine Woodland and the open Northern Rockies Western Larch Savanna, with a grassland-shrub mosaic of pine reedgrass (Calamagrostis rubescens), big sagebrush (Artemisia tridentata), and bearberry (Arctostaphylos uva-ursi). Mid-elevation drainages support Southern Rockies Mixed Conifer Forest and Rocky Mountain Lodgepole Pine Forest, with thimbleberry (Rubus parviflorus), single-flowered clintonia (Clintonia uniflora), and Oregon boxleaf (Paxistima myrsinites) in the understory. The upper ridges carry Rocky Mountain Dry Subalpine Spruce-Fir Forest of Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa), with whitebark pine (Pinus albicaulis) on the high knobs. Northern Rockies Subalpine Grassland and Rocky Mountain Subalpine Meadow occupy the open ribs between the summits, scattered with fairy slipper (Calypso bulbosa), tall white bog orchid (Platanthera dilatata), and ground juniper (Juniperus communis).

Forest carnivores move through the unbroken cover. Canada lynx (Lynx canadensis) hunts snowshoe hare through the lodgepole and spruce-fir stands, and the area falls within the range of North American wolverine (Gulo gulo luscus). Columbian ground squirrel (Urocitellus columbianus) occupies the dry meadow benches below the summits; North American red squirrel (Tamiasciurus hudsonicus) caches conifer cones in the closed canopy. Calliope hummingbird (Selasphorus calliope) and rufous hummingbird (Selasphorus rufus) feed on yellow beardtongue (Penstemon confertus), yellow columbine (Aquilegia flavescens), and sagebrush buttercup (Ranunculus glaberrimus) at the meadow margins. Cassin's finch (Haemorhous cassinii) and olive-sided flycatcher (Contopus cooperi) work the upper conifer canopy. The cold tributaries of North Fork Deadman Creek and North Fork Sherman Creek hold threatened bull trout (Salvelinus confluentus). Whitebark pine, listed as endangered on the IUCN red list, anchors the high stands. Portions of this area fall within the potential range of several federally listed species; see the Conservation section for details.

A visitor climbing from the lower drainages to the paired summits of Twin Sisters moves first through dry ponderosa pine and western larch with bunchgrass and bearberry underfoot, then into closed lodgepole forest as the elevation rises. King Creek and Camp Creek run cold off the north faces of King Mountain and U.S. Mountain. The upper ridge of Twin Sisters opens onto subalpine meadow with scattered whitebark pine and views east to the Selkirk crest above the Columbia and west across the Kettle Crest to Republic.

Twin Sisters is a 13,051-acre Inventoried Roadless Area in the Colville National Forest of Ferry County, Washington, within the Pacific Northwest Region of the U.S. Forest Service. The area is managed within the Three Rivers Ranger District and is protected under the 2001 Roadless Area Conservation Rule.

The original inhabitants of what is now Ferry County were several semi-nomadic Indian tribes, with the Colville predominating; their principal fishing, rendezvous, and trading point was Kettle Falls on the Columbia River [1]. Archaeologists estimate that the Colville Confederated Tribes and the Spokane Tribe caught more than 1,000 salmon a day at Kettle Falls during peak runs [3]. In 1811, North West Company cartographer David Thompson reached Kettle Falls; the Hudson's Bay Company built Fort Colvile on the east bank of the Columbia in 1825 [1]. In April 1872, the Colville Reservation was established by executive order over a vast portion of present Ferry and Okanogan counties [1]. The Confederated Tribes of the Colville Reservation today comprise twelve bands of indigenous peoples.

Industrial use of the lands surrounding Twin Sisters began in the 1890s. On July 1, 1892, the United States government purchased the northern half of the Colville Reservation for $1.5 million, about $1.00 per acre [1]. After gold was discovered in the region, the northern half was opened to prospectors on February 21, 1896 [1][2]. John Welty filed the first legal mining claim in the Republic area that year, and Tom Ryan and Phil Creaser soon located the Republic Mine on Eureka Creek [2]. The district boomed under Spokane mining tycoon Patrick "Patsy" Clark; the Republic Gold Mining and Milling Company issued its first dividend of $150,000 on October 10, 1898 [1][2]. By 1900, roughly 12,500 mining claims had been staked across Ferry County [1]. Timber followed quickly: Patrick H. Walsh erected the first sawmill in Ferry County in 1897, and the San Poil Lumber Company was incorporated in May 1899 [1]. Ferry County itself was carved from Stevens County in February 1899, with Republic as county seat [2].

Federal forest management came in 1907. On March 1, 1907, President Theodore Roosevelt set aside approximately 870,000 acres of former reservation land as the Colville Forest Reserve — the unit that became today's Colville National Forest [1][4]. The forest covers about 1.5 million acres of northeastern Washington and is administered through five ranger districts, including the Three Rivers Ranger District in which Twin Sisters lies [4]. During the 1930s, the Civilian Conservation Corps built miles of forest road and strung electric lines through the county, linking fire lookouts and ranger stations and opening the previously inaccessible Kettle Range [1]. The state highway over Sherman Pass to Kettle Falls — which crosses the watershed just south of Twin Sisters — was completed in 1953 [2].

Vital Resources Protected

• Cold Headwater Stream Integrity: The North Fork Deadman Creek begins inside this roadless area, fed by King Creek, Camp Creek, Wash Creek, and High Bridge Creek; the North Fork Sherman Creek heads on the southern slopes. These streams flow through Rocky Mountain Subalpine Streamside Woodland and Northern Rockies Foothill Streamside Woodland with intact riparian canopy. The roadless condition preserves the shaded, sediment-stable channels and woody-debris recruitment that threatened bull trout require for spawning and rearing in the upper Columbia watershed.

• Lynx and Wolverine Movement Corridor: Continuous Rocky Mountain Lodgepole Pine Forest, Southern Rockies Mixed Conifer Forest, and Rocky Mountain Subalpine Spruce-Fir Forest carry Canada lynx and North American wolverine across the Kettle River Range. Without roads, the area functions as part of the cross-border connectivity between the Cascades and the Selkirks, supporting wide-ranging carnivores that cannot tolerate fragmented or human-trafficked corridors.

• Whitebark Pine and Subalpine Refugia: Stands of threatened whitebark pine on the high knobs around Twin Sisters, U.S. Mountain, and Mack Mountain anchor an upper-elevation community of Engelmann spruce, subalpine fir, and Northern Rockies Subalpine Grassland. Roadless status maintains the seed-caching cycle between whitebark pine and Clark's nutcracker, preserves climate-refugia habitat for high-elevation species, and shields these stands from the road-associated disturbance that accelerates white pine blister rust and mountain pine beetle outbreaks.

Potential Effects of Road Construction

• Sedimentation and warming of bull-trout streams. Road construction on the steep slopes around U.S. Mountain, King Mountain, and the upper Sherman drainage would expose mineral soils to chronic surface erosion. Sediment delivered to North Fork Deadman Creek and North Fork Sherman Creek would embed the clean gravels that bull trout require for redd construction, while canopy removal at crossings would raise summer water temperatures past the thermal threshold for cold-water salmonids. These effects compound across the watershed and persist for decades.

• Fragmentation of the lynx and wolverine corridor. A road through the Kettle Crest would sever the unbroken forest band that supports lynx and wolverine movement between the Cascades and the Selkirks. Open roads increase mortality risk for these wide-ranging species through vehicle collisions, displacement from preferred cover, and elevated human access for poaching and incidental take. Loss of connectivity in this corridor is functionally irreversible once the road network expands.

• Invasive species spread and edge effects in subalpine communities. Road shoulders create linear corridors of disturbed bare soil through which non-native plants documented in the region — common tansy, oxeye daisy, spotted knapweed, and Dalmatian toadflax — can colonize whitebark pine stands and the open meadows around Twin Sisters. Once established, these species displace the native bunchgrass, bearberry, and subalpine forb communities that support pollinators and ground squirrels. Edge effects from each road segment also dry adjacent forest interior and accelerate beetle and disease pressure on whitebark pine.

Twin Sisters covers 13,051 acres of Kettle River Range backcountry in the Colville National Forest of Ferry County, Washington, within the Three Rivers Ranger District. The area is reached from State Route 20 between Republic and Kettle Falls, including the Sherman Pass Scenic Byway corridor at the south end. Trailheads on the area boundary include Ryan's Cabin, Stickpin, and Old Stage; the Wapaloosie Campground provides developed staging.

Hiking and backpacking. The Twin Sisters Trail (#109, 6.6 miles) traces the high ridge across the paired summits and serves as the area's principal long route. The Mac/King Trail (#98, 8.0 miles) crosses the Mack Mountain and King Mountain ridge. Shorter approaches include the U.S. Mountain Trail (#76, 3.2 miles) to the summit of U.S. Mountain and the U.S. Spur (#12600, 2.7 miles). All routes run on native-material tread, climbing from dry ponderosa pine and western larch at the lower elevations through closed lodgepole forest into open subalpine meadow on the high ridge. Backpackers can link the Twin Sisters and Mac/King trails into longer Kettle Crest traverses with dispersed camping at unimproved sites.

Horseback travel. The U.S. Mountain Trail (#76) is signed for horse use on native-material tread, and the longer Twin Sisters (#109) and Mac/King (#98) routes also accommodate stock. Plan extended trips around water at King Creek, Camp Creek, and the North Fork Sherman Creek.

Fishing. The cold tributaries of North Fork Deadman Creek and North Fork Sherman Creek carry threatened bull trout. Bull trout are protected under Endangered Species Act listing; consult current Washington Department of Fish and Wildlife regulations before fishing, and confirm catch-and-release status. Nearby low-elevation waters at Curlew Lake provide developed fishing opportunities outside the roadless block.

Hunting. General-season opportunities under Washington WDFW seasons include mule deer, white-tailed deer, black bear, and forest grouse across the area's forest mosaic. Federal listings apply to Canada lynx and North American wolverine; hunters must positively identify quarry. Limited-quota tags may apply to other game species; check current rules.

Birding. Thirteen eBird hotspots within 24 km record between 69 and 162 species; the most active is the Rail Trail Wetland at Curlew Lake with 147 checklists. Documented species across this landscape and the surrounding Colville National Forest include calliope hummingbird and rufous hummingbird at the meadow margins, Cassin's finch and olive-sided flycatcher in the upper conifer canopy, yellow-billed cuckoo in riparian shrub, and bald eagle along the lower drainages.

Snow and winter travel. The Sherman Pass corridor south of the area carries Forest Service snow routes used for cross-country skiing and snowshoeing in winter; the upper elevations of Twin Sisters hold deep snowpack into spring. Consult Northwest Avalanche Center guidance before backcountry travel.

Roadless context. Recreation here depends on the absence of roads. The cold tributaries of Deadman and Sherman creeks hold the bull trout populations that sustain catch-and-release fishing. Unfragmented forest and the whitebark pine summits sustain the Canada lynx, North American wolverine, and high-elevation wildlife that observers and photographers come to see. The Kettle Crest routes — Twin Sisters, Mac/King, and the U.S. Mountain spur — remain quiet ridge traverses because no motorized access penetrates the high country between the developed corridors at Sherman Pass and the Curlew Lake basin.