The Observatory Sun Valley, a Viceroy Resort

The Observatory Sun Valley, a Viceroy Resort, is taking reservations for stays from 30 October 2026 at the corner of Main and River streets in downtown Ketchum, the town next to the City of Sun Valley. Announced in 2025 as The Harriman, it pairs 73 rooms with 12 penthouse residences, a 5,000-square-foot spa and a rooftop observatory with a professional telescope inside the first Dark Sky Reserve in the United States.

The place

300 River Street East, at the corner of Main Street, in downtown Ketchum. Ketchum is a separate municipality from the City of Sun Valley, about a mile away at the foot of Bald Mountain, and it is the commercial centre of the Wood River Valley: the resort takes the Sun Valley name, as the local press and the hotel itself do, but the address is in Ketchum.

The concept

The project has changed identity twice. It was first developed under the Appellation banner, was announced in May 2025 as The Harriman, a Viceroy Resort, in tribute to Averell Harriman, the Union Pacific Railroad chairman who created Sun Valley in 1936, and now trades as The Observatory. It is a roughly 150,000-square-foot building pairing 73 guest rooms with 12 single-level penthouse residences for sale, developed by majority owner Andrew Blank, with de Reus Architects and Hornberger+Worstell as architect of record and interiors by Fatima Silva of FDG Design Group. The opening slipped from the June 2026 date announced with the Viceroy deal; reservations are now open for stays from 30 October 2026. Its distinguishing feature is astronomical rather than alpine: Ketchum and Sun Valley sit at the southeastern edge of the Central Idaho Dark Sky Reserve, the first such reserve designated in the United States and one of only a dozen worldwide, and the hotel has built a rooftop observatory with a professional-grade telescope and a terrace bar around it.

Dining & wellness

Three venues are named: Joan, Odin's Corner and Andy's Watershed at The Observatory. The wellness floor covers about 5,000 square feet with six treatment rooms, an indoor thermal pool, cold plunge, sauna and steam rooms, alongside a 1,130-square-foot fitness centre and an outdoor pool. The rooftop observatory and its terrace bar are the signature space, with a guided sky tour listed as coming later.