Civil Engineering in Ketchum, Idaho.

Working in Ketchum

Ketchum is the northern resort anchor of the Wood River Valley in Blaine County, adjacent to Sun Valley and Bald Mountain (Baldy) ski terrain. The city combines a dense downtown core with hillside residential neighborhoods and a compressed development envelope bounded by the Big Wood River, Trail Creek, Warm Springs Creek, and steep surrounding terrain — which drives an unusually heavy design review, floodplain, and hillside regulatory overlay compared to most Idaho cities of its size.

• Planning & Zoning: City of Ketchum Planning & Building Department, 191 5th Street West, Ketchum, ID 83340 — (208) 726-7801, [email protected]. Planning & Building page.
• Comp Plan: Ketchum 2025 Comprehensive Plan (adopted September 11, 2025, superseding the 2014 plan); a companion Land Development Code update was adopted December 2025. Comp Plan page · Code update project.
• Engineering Considerations:
  • Mountain Overlay District (hillside/slope): Ketchum's Mountain Overlay District (established 1989) limits new building on slopes of 25% or greater; building envelopes on new parcels must be located outside 25%+ slope areas, and projects within the overlay require a Mountain Overlay Design Review application.
  • Ketchum design review: Downtown and Warm Springs base-area development is subject to design review beyond standard zoning — including the Community Core Building Height Diagram and Warm Springs Base Area Design Guidelines — substantively shaping massing, materials, and street-level treatment.
  • Big Wood River / Trail Creek / Warm Springs Creek floodplain: A Floodplain Overlay Application is required for any development within the SFHA (Special Flood Hazard Area) or adjacent to the Big Wood River, Warm Springs Creek, Trail Creek, or their tributaries. Ketchum has participated in NFIP since 1978; major flood events in 1983, 2006, and 2017 inform current regulatory posture.
  • Wildfire WUI: Ketchum sits in a wildfire WUI (Wildland-Urban Interface) area with hillside residential exposure on multiple aspects; Idaho Firewise guidance applies, and recent flood hazard increases are partly attributed by city staff to upstream wildfire effects.