Buying Land in Custer County, Idaho

A vast, mostly public-land county: what that means for access and expectations

Custer County covers roughly 4,937 square miles -- the third-largest county in Idaho by land area -- but housed only about 4,275 residents at the 2020 Census, spread across Challis (the county seat, population roughly 944 in 2024), Mackay, the small resort town of Stanley, and a scatter of unincorporated communities. Close to 90% of the county's total land is federally owned, primarily within the Salmon-Challis National Forest, the Sawtooth National Forest, and the Sawtooth National Recreation Area, which itself covers 730,864 acres partly within the county. In some specific Forest Service management areas inside Custer County, over 99% of the land is federally administered, with private inholdings representing roughly 1%. For a land buyer, this means private parcels here are genuinely more likely to border public land than another private owner -- confirm access routes, any easements across federal land, and grazing or special-use permit arrangements tied to a specific parcel as a standard, not optional, step.

Zoning: a real 20-acre agricultural minimum, and a documented pre-2003 exception

Custer County's Zoning Ordinance No. 2007-09 establishes several base zoning districts, including a Transitional/Agricultural (T-A) district with a 2.5-acre minimum lot size, Residential and Commercial districts with a 9,000-square-foot minimum, an Industrial district with a one-acre minimum, and a standalone Agriculture (A) zone carrying a 20-acre minimum lot size -- a meaningfully larger baseline than many county's general-purpose agricultural zoning. The ordinance also documents a grandfather provision for pre-November 2003 parcels and a separate permit route for smaller splits; see the dedicated subdividing-land page below for exactly how both work.

For a buyer evaluating a larger tract with subdivision or lot-split potential in mind, confirm both the applicable zone and the parcel's specific division history and eligibility directly with Custer County Planning and Zoning before relying on any subdivision assumption.

Thompson Creek Mine's restart: a real economic shift worth factoring in

The Thompson Creek molybdenum mine, roughly 30 miles southwest of Challis in the Bay Horse Mining District, is the fourth-largest primary molybdenum mine in the world and, historically, Custer County's largest employer whenever it has been in production. Mining ended its seventh operational phase in 2014, after which the mine sat on care-and-maintenance for a decade. In September 2024, owner Centerra Gold announced a restart of operations, with production currently targeted for the second half of 2027 as part of Centerra's broader Molybdenum Business Unit.

This is a genuinely significant, documented development for the county's economy -- a restart at this scale historically has meant real local employment growth and increased demand for workforce housing near Challis. It's reasonable context for a buyer considering land in the area over a multi-year horizon, though this page cannot and does not predict how it will affect any specific parcel's value or the pace of local development.