120 Keystone St, Sun Valley, ID 83353 (MLS# 26-334170)

$5,250,000

120 Keystone St
Sun Valley, ID 83353
MLS# 26-334170

Expansive, sun-drenched pastures with Bald Mountain as your backdrop, the ultimate Sun Valley equestrian setting.

1 / 37

Unobstructed, panoramic views of the iconic Bald Mountain bowls from your private 52-acre ridge.

Enjoy immediate visual trail reports for Sun Valley’s Bald Mountain. 120 Keystone St offers an unobstructed vantage point of the world-class ski runs and weather conditions right from your property.

Captivating up-valley views showcasing the rugged beauty and pristine wilderness of Central Idaho.

A signature on-site pond creates a dramatic sense of arrival, providing a natural acoustic buffer for this private Sun Valley estate, while documented geothermal potential offers a unique, sustainable amenity.

A rare 52-acre offering across two separate, deeded parcels, providing unmatched privacy and versatile development or family compound potential.

Springtime at 120 Keystone: 52 acres of vibrant, emerald-green hillsides and pristine mountain air, offering a truly 'private park' experience.

A secluded ground-level view showcasing the private, manicured grounds and sprawling front acreage of this Sun Valley legacy estate at 120 Keystone St.

Dual-parcel configuration at 120 Keystone, offering significant land-use flexibility bordering Forest Service land.

Preliminary analysis identifies a premier conceptual building envelope on the 18.6-acre front parcel, strategically positioned to maximize panoramic Bald Mountain views and natural solar orientation.

The property’s private gated driveway is a scenic masterwork, offering immediate immersion into the Sun Valley backcountry and establishing 120 Keystone St as a true legacy retreat.

Preliminary analysis suggests a strategic opportunity to consolidate the 33.5-acre back parcel with the front acreage through a potential U.S. Forest Service (USFS) land swap, creating a more contiguous 50+ acre Sun Valley estate.

Secure, gated entry ensures total privacy for this premier 52-acre Sun Valley estate, offering a rare sanctuary bordering U.S. Forest Service land.

Preliminary site analysis identifies a premier conceptual building envelope on the 33.5-acre back parcel, positioned to maximize panoramic Bald Mountain views and natural topography.

A signature year-round pond, fed by senior 1883 water rights, creates a stunning sense of arrival as you enter the private gated drive of this 52-acre Sun Valley estate.

A rare legacy estate featuring senior 1883 water rights and on-site geothermal potential, offering a unique sustainable energy opportunity in the Sun Valley market.

Experience the seasonal 'green-up' of the Wood River Valley from your private ridge; a rare look at the estate's verdant landscape and geothermal-fed vitality.

A private gated entrance serves as an exclusive trailhead into Keystone Gulch, providing direct backcountry access to the summit of Johnstone Peak and the surrounding wilderness.

Nestled within Sun Valley’s exclusive Elkhorn neighborhood, 120 Keystone St offers a secluded mountain retreat with a private trailhead providing direct access to the Sawtooth National Forest backcountry.

Breathtaking fall vistas overlooking the valley; a prime season to enjoy the local wildlife and the crisp mountain air from your private ridge.

The 33.5-acre back parcel offers a strategic USFS land swap opportunity. By exchanging hillside acreage for contiguous valley floor space, an owner can significantly expand the building envelope and maximize development density at 120 Keystone St.

Stunning Bald Mountain Views Near Sun Valley Resort Skiing.

Detailed boundary overlay via Land.id illustrating the two deeded parcels, topography, and the seamless border with Forest Service land.

Privacy meets proximity at 120 Keystone St, a gated Sun Valley estate minutes from Ketchum, Bald Mountain skiing, and the best of South Central Idaho's mountain lifestyle.

Property Description
Sun Valley Legacy Estate & Development Masterpiece. Discover the pinnacle of mountain living at 120 Keystone St, a premier 52-acre legacy estate in the exclusive Elkhorn area of Sun Valley, Idaho. This rare dual-parcel landholding (18.6 & 33.5 acres) offers a breathtaking canvas for a private horse property or a high-end boutique residential development. Search address on YouTube for video tours.

Details

Maps

Documents

Location Tax and Misc

Current Price: $5,250,000

Area: Sun Valley

Street Number: 120

Street Name: Keystone

Street Suffix: St

State/Province: ID

Zip Code: 83353

County: Blaine

Subdivision: Other

Assessor's Parcel #: RP1M0000000750

List Price: $5,250,000

Lot Acreage Info

Parcel SqFt Apx: 2265120

General Property Description

Sub Type: Single Family Residence

Realtor.com: Vacant Land

Waterfront if Appcbl: Yes

Geo Lat: 43.679711

Geo Lon: -114.301652

Contract Info

Status: Active

List Date: 2026-03-12

Concession Negotiable: Yes

Concession Remarks: Please Call Listing Agent.

Directions: Keystone Rd in Elkhorn, Sun Valley

Property Features

Zoning: BC/R-10

Road Surface: Dirt

Road Access: Easement; Private

Utilities On Site: Electric; Septic; Telephone; Well-Individual

Waterfront: Pond; See Realtor Remarks; Wetlands

Features Exterior: Barn/Shed; Corral; Deeded Water Rights; Fence; Outbuildings; Undergrnd Utilities; Views; Horses Permitted; Leased Propane Tank

Documents: Other

Other Disclosures: Avalanche; Wetlands

Terms: 1031; Cash; OWC

Utilities at Road: Electric; Telephone

Supplements

The Ultimate Equestrian & Outdoor Retreat: Bordering U.S. Forest Service land, the estate provides unparalleled private canyon access for horseback riding and hiking. Secure your legacy with senior 1883 water rights (irrigation/stock) and a high-yield well. The property features a serene pond with on-site geothermal potential, creating a year-round alpine oasis for wildlife and residents alike. Developer Upside & Infrastructure: Zoned BC/R-10 with patented mining claims, the land is ready for a luxury compound or multi-homesite project. Utilities (well, septic, buried power) are already installed. Significant value-add opportunities exist through a potential 18-acre USFS land swap, and recent analysis indicates potential for a third building site, offering even greater density and investment value. Strategic Opportunity: Located minutes from Ketchum and Sun Valley Resort, this $10.5M-appraised asset is offered with flexible acquisition options. Owner will carry paper for up to five years with 50% down; other terms are negotiable. Control one of the last large private holdings in a supply-constrained market.

Listing Documents

Mt West Avy Report

120 Keystone Ground Water Right

120 Keystone Irrigation/Stockwater Right

USFS Diagram

120 Keystone Septic Report

120 Keystone Power and Water

120 Keystone Well Log

120 Key. BC Parcel Determination 2023

Listing Office: Keller Williams Sun Valley Southern Idaho

Listing Agent: James Tautkus

Last Updated: March - 12 - 2026

The information being provided is for consumers' personal, non-commercial use and may not be used for any purpose other than to identify prospective properties. This serves as notice to those using the website that they may not use the data found here as a basis for a business enterprise. Information provided by Sun Valley Board of Realtors Multiple Listing Service is deemed reliable but not guaranteed. Property of the Sun Valley Board of Realtors. Information provided by Sun Valley Board of Realtors Multiple Listing Service is deemed reliable but not guaranteed. The information on this sheet has been made available by the MLS and may not be the listing of the provider.