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

120 Keystone St, Sun Valley, ID 83353

$4,900,000

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

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

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

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.

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.

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.

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

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.

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

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.

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.

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.

Utilities on site and identified locations.

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

Proposed Forest Service Land Swap application.

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

Property Type: Vacant Land Lot Size (sq. ft.): 2,265,120 Status: Active

Current Price: $4,900,000 List Date: 3/12/2026 Last Modified: 8/31/2026

Overview

Description

Discover 120 Keystone St, a premier 52-acre legacy estate for sale in the exclusive Elkhorn area of Sun Valley, Idaho. Positioned just minutes from downtown Ketchum and the Sun Valley Resort, this rare dual-parcel landholding--comprising 18.6 and 33.5 acres--offers an unparalleled opportunity for a private equestrian compound or a boutique luxury residential development.

Supplements: Bordering U.S. Forest Service land, the property provides direct, private canyon access for horseback riding, hiking, and outdoor recreation right from your back door. Appraised at $10.5M, this Sun Valley real estate asset combines pristine natural amenities with exceptional utility. The land is anchored by senior 1883 water rights for irrigation ... (Read more)

Listing Details MLS# 26-334170

Location Tax and Misc

Area: Elkhorn in 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

Lot Acreage Info

Parcel SqFt Apx: 2265120

General Property Description

Sub Type: Single Family Residence
Realtor.com: Vacant Land
Waterfront if Appcbl: Yes

Contract Info

Concession Negotiable: Yes
Concession Remarks: Please Call Listing Agent.
Directions: Located at the gated, private terminus of Keystone Street within the exclusive Elkhorn community of Sun Valley, Idaho.

Location, Tax and Misc

Legal: Elkhorn 46, Keystone 41 A, Carbon Hill 74 A, SEC 15 4N 18E
List Price Per Acres: 94230.77
Taxes: 1206.84
Tax Year: 2025

Lot / Acreage Info

Parcel Acres Apx: 52
Parcel Size Per: Realtor

More Information

Remarks & Misc

Possession: On Closing

Documents

Other: Yes

Features Exterior

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

Road Access

Easement: Yes
Private: Yes

Road Surface

Dirt: Yes

Terms

1031: Yes
Cash: Yes
OWC: Yes

Waterfront

Pond: Yes
See Realtor Remarks: Yes
Wetlands: Yes

Zoning

BC/R-10: Yes

Other Disclosures

Avalanche: Yes
Wetlands: Yes

Utilities at Road

Electric: Yes
Telephone: Yes

Utilities On Site

Electric: Yes
Septic: Yes
Telephone: Yes
Well-Individual: Yes

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

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: August - 31 - 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.