Castle Rock Ranch

$1,950,000 Mackay, ID 80± Deeded Acres

Executive Summary

The 80± acre Castle Rock Ranch is located approximately 30 miles northeast of the resort community of Ketchum/Sun Valley over Trail Creek Pass. The East Fork of the Big Lost River, a beautiful mid-sized freestone stream, flows through the property for over a half-mile providing outstanding trout fishing throughout its length. Star Hope and Wildhorse Creeks (two of the East Fork's main tributaries) along with the North Fork of the Big Lost and main stem Big Lost are only a short distance away from the property and offer additional high-quality, easily accessible fishing opportunities. A very tasteful 2,054± square foot, four-bedroom/two-bath log fishing cabin (which is being offered furnished) is perched above the East Fork and offers enchanting views of the river and the surrounding White Knob and Pioneer mountains. The Salmon-Challis National Forest borders the ranch on three sides and provides miles of hiking, horseback riding, big game hunting, and other backcountry recreation. Wildlife in the East Fork Valley includes elk, mule deer, moose, antelope, and upland game birds.

Just the Facts

  • 80± acre retreat bordering the Salmon-Challis National Forest
  • Over a half-mile of the East Fork of the Big Lost with excellent trout fishing plus abundant fishing opportunities nearby
  • One of just a few private holdings along the East Fork
  • 30 miles from Ketchum/Sun Valley over Trail Creek Pass
  • Beautiful, furnished, four-bedroom log home with high-end finishes
  • Miles of hiking and riding right from the property plus big game hunting and wildlife viewing
  • Located in hunt unit 50 and the Pioneer elk zone
  • Irrigation right for 45 acres
  • Nearly 7,200 feet in elevation
  • Annual property taxes are approximately $7,700

General Description

Bordered by US Forest Service lands, the Castle Rock Ranch is part of an old ranching homestead and one of only a handful of deeded properties along the East Fork of the Big Lost River. The namesake of the ranch, Castle Rock (elevation 8,600 feet), is a rugged, complex mountain rising a short distance northeast of the property and made up of numerous rock towers and sheer walls. A hike from the ranch to Castle Rock or to its cousin just beyond, Porphyry Peak (elevation 9,950 feet), is a wonderful way to spend part of the day. The willow-lined East Fork flows through the ranch for over a half-mile from east to west and provides excellent trout fishing and habitat for moose, mule deer, beavers, and songbirds. The owner’s home is perched above the East Fork in a private setting at the end of the main drive and commands outstanding views of the river and the surrounding mountains. The property is perimeter-fenced and cross-fenced making it ideal for keeping horses. A railcar bridge situated just upstream of the residence spans the river and provides access to the north half of the property and adjacent Forest Service lands. Copper Basin Road, a gravel road maintained seasonally by Custer County and the Forest Service, provides access to the ranch and parallels the south boundary of the property. 

Broker's Comments

Castle Rock Ranch is a beautiful mountain retreat in a secluded setting approximately 30 miles from Ketchum/Sun Valley offering top-notch trout fishing and unlimited access to some of Idaho’s best backcountry. There are very few deeded properties situated along the East Fork of the Big Lost, and it is rare for a property of this caliber in this location to come onto the market. 

Learn about the locale


The Castle Rock Ranch is located in the upper Lost River Valley approximately 30 miles northeast of the well-known all-season resort community of Ketchum/Sun Valley and 40 miles northwest of the ranching community of Mackay. Access from Sun Valley is a 45-minute drive via Trail Creek Pass and Copper Basin Road (both gravel roads) from May through November. As mountain snowfall begins to accumulate late in the year, Trail Creek Pass and Copper Basin Road close until spring and access to the property is limited to snow machines and cross country skiing. 

Friedman Memorial Airport (SUN) in Hailey, 15 miles south of Ketchum/Sun Valley, is the nearest commercial airport and offers regular air service on Delta, United, and Horizon Airlines. Idaho Falls, approximately two hours southeast of the property, provides alternate commercial air service out of Idaho Falls Regional Airport (IDA) on Delta and United. Mackay is home to a 4,400’X60’ asphalt airstrip capable of accommodating larger twin-engine aircraft. Of interest to backcountry pilots, the property is equidistant from two state-owned airstrips -- the 4,450’X100’ Twin Bridges Airport and the 4,700’X100’ Copper Basin Airport -- each located on public lands less than 10 miles from the ranch. These turf runways feature windsocks, perimeter markings, and tie downs.


The Lost River Valley is considered one of Idaho’s most scenic areas and is among the state’s top regions for outdoor recreation. The massive Lost River Range flanks the east side of the valley and spans over 70 miles from Arco to Challis. The Lost Rivers claim seven of Idaho’s ten peaks over 12,000 feet, including Mt. Borah, the state’s highest peak at 12,662 feet. Two other formidable mountain ranges, the Pioneers and White Knobs, extend westward from the valley all the way to Ketchum/Sun Valley providing incredible vistas and miles of roadless backcountry to explore. The Big Lost River originates from high mountain tributaries and meanders east and then south through the valley, providing irrigation water for farms and ranches as well as outstanding trout fishing opportunities. 

Sun Valley, Ketchum and the other Wood River Valley communities of Hailey and Bellevue are an easy drive from the property and offer a multiplicity of summer and winter activities, including golf, hiking, fly fishing, mountain bike riding, and world-class downhill and Nordic skiing. One will also find there numerous gourmet restaurants, art galleries, shopping opportunities, and cultural events to enjoy.

Mackay, population 565, lies at the heart of the Lost River Valley and serves as the local service and social center. It is an agriculturally based community, although its roots go back to the mining days in the early 20th century. All general amenities can be found in Mackay, including groceries, fuel, restaurants, and ranch and hardware providers. 


The elevation of the ranch is approximately 7,165 feet. The climate is best described as semi-arid with annual precipitation from 10 to 14 inches and over 300 sunny days per year. Summer temperatures at this altitude are close to ideal with highs reaching the 80s and then cooling to the mid-40s at night. Winters are cold with snowfall varying depending on annual moisture patterns. 

Learn more about the property

Acreage (Deeded & Leased)

80 deeded acres, more or less.

Deeded Acres: 80±
Total Leased Acres:
Total Acres: 80±


Castle Rock Ranch boasts an inviting, comfortable, and well-appointed 2,054 square foot, two-story log residence constructed in 1997. Before entering the home, one is drawn to the porch overlooking the East Fork where one only hears the sound of the river passing by below. This is an ideal place to relax and contemplate an upcoming day of fishing or unwind after a full day of exploring the area’s highlands and backcountry. The main floor of the home comprises the master bedroom and a full bath, kitchen with granite countertops, a laundry area and mud room, and a spacious living and dining area with a large river rock fireplace. The second floor features three bedrooms and a full bath. There are exposed log walls and pine floors throughout the home which adds to its charm and authenticity. The house is served by buried power lines, a domestic well, and its own septic tank and drain field. Heating is via electric baseboard heat. There is no phone line to the property nor is there cell phone coverage in this part of the valley, although one can utilize satellite telephone service as well as satellite internet VoIP for telephone communications. The lawn and attendant landscaping are watered by an underground sprinkler system. The home is being offered furnished. 

Water Resources

The owner of Castle Rock Ranch is entitled to irrigate an estimated 45 acres of the property under water right no. 34-624 utilizing water from Deer Creek, a nearby tributary to the East Fork. 

Water Rights

Water Right 34-624


Annual property taxes are approximately $7,700.

Learn about the recreational amenities

Recreational Considerations

Rivaling its better known neighbor to the west, Sun Valley, the upper Lost River Valley offers stunning scenery and a variety of high-quality outdoor recreation opportunities. Trout fishing, wingshooting, big game hunting, horseback riding, mountain bike riding, backcountry skiing, hiking and wildlife viewing can all be outstanding and enjoyed either on or minutes away from Castle Rock Ranch. 

Trout fishing is among the most highly pursued activities in the area. From its spring creek-like beginning in an area called “the Swamps” upstream of the ranch to its convergence with the North Fork to become the Big Lost River, the East Fork is a gem of a mid-sized freestone stream that offers a variety of fishing scenarios in a relatively short distance. Rainbows, Snake River fine-spotted cutthroats, and brook trout are the quarry and are found in abundance throughout the East Fork and upper Big Lost. Blue winged olives, green drakes, golden stones, and caddis are standard hatch fare during summer months; however, matching the hatch isn’t required to take fish, as day in and day out high floating attractor patterns are reliable producers. Castle Rock Ranch features an outstanding reach of the East Fork as riffles, deeper runs and undercut banks within this stretch all hold fish. Beyond the ranch, one finds excellent access to the East Fork across Bureau of Land Management (BLM) and Forest Service lands. There is also outstanding access across public lands to the East Fork’s main tributaries, Star Hope and Wildhorse creeks, as well as to the North Fork and the main stem Big Lost just a few miles west of the ranch. 

For the upland hunter, chukar partridge are abundant on rocky slopes while blue grouse are common on the higher elevation Forest Service lands. All of Idaho’s big game species can be found within proximity to the ranch. 

For the hiker or horseback rider, the upper Big Lost area, including nearby Copper Basin (a remote and stunningly beautiful high elevation valley rung by peaks over 11,000 feet beginning just east of the ranch), enjoys some of the state’s most spectacular high country. In addition to unlimited cross-country hiking and riding opportunities, an extensive public lands trail network provides access to the area’s vast alpine riches. 

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