Idaho

Buying Land in Lemhi County, Idaho

Salmon and the Lemhi Valley sit deep in some of Idaho's most mountainous, most public-land-dominated country, with private land largely defined by its relationship to the surrounding Salmon-Challis National Forest and BLM holdings. Before zoning questions, the more basic ones here are how much private land actually exists around a parcel and whether it has real, legal road access -- this page covers what's specific to Lemhi County.

Roughly 80% of the County Is Federal Land -- Confirm What's Actually Private

Case-by-case / verify locally

A widely cited estimate puts roughly 80% of Lemhi County's total land area under federal administration, primarily the Salmon-Challis National Forest (which the Forest Service itself describes as covering most of its mountainous terrain in Lemhi County) along with additional Bureau of Land Management land managed through the Salmon Field Office (nearly 500,000 acres focused on grazing, mining, and multiple-use access). This figure was not independently confirmed against a precise, current county-level land-ownership dataset for this page, and should be treated as a directional estimate rather than an exact number. What matters more for a specific transaction is whether a given parcel is a genuine private inholding surrounded by public land (which can affect access, and can also mean neighboring public land use, like grazing allotments or seasonal hunting activity, is a fact of life) -- confirm ownership patterns around any specific parcel using the county GIS/parcel viewer or BLM/Forest Service land status maps before assuming it's typical, unrestricted private land.

A Real, Documented Setback Along the Salmon and Lemhi Rivers

Case-by-case / verify locally

Lemhi County's development code sets a specific stream-corridor standard for the Salmon and Lemhi Rivers: new development must maintain at least 25 feet from the average annual high-water mark, and the county's defined "stream corridor" includes the entire mapped special flood hazard area along with associated wetlands and riparian areas -- a broader zone than the 25-foot setback figure alone suggests. Given that river frontage and fishing/recreational access along the Salmon and Lemhi Rivers is one of the county's biggest land-value drivers, this is a genuinely important, county-specific rule to understand for any riverside parcel: confirm the exact buildable envelope on a specific lot, not just the property line, directly with the county before assuming where a home site can go.

Confirm Legal Road Access Before Assuming It Exists

Case-by-case / verify locally

Lemhi County's subdivision and special-use permit process requires an applicant to document the location, width, surface type, and legal status (existing county road, private easement, or otherwise) of all roads, drives, and rights-of-way serving a property, and the county separately administers its own Access Permit process for new approaches onto county roads. In a county this dominated by national forest and BLM land, a parcel's practical access may run through a Forest Service road (which can carry seasonal closures or use restrictions) or a private easement rather than a public county road. Before buying, confirm the specific legal basis of a parcel's road access -- not just whether a road physically reaches it -- directly with Lemhi County Planning & Zoning/Building and, if relevant, the Salmon-Challis National Forest or BLM Salmon Field Office.

Septic Runs Through Eastern Idaho Public Health, Not the County

Could not confirm

As with the rest of Idaho, septic permitting is administered by a regional health district under statewide IDEQ rules, not by Lemhi County itself (see the state hub). Lemhi County falls under Eastern Idaho Public Health, the same district that covers Jefferson County (also on this site) along with Bonneville, Clark, Custer, Fremont, Madison, and Teton counties. Confirm current site-evaluation scheduling and any locally observed soil or terrain constraints directly with the district before assuming a straightforward approval -- mountainous terrain and shallow soils in parts of the county can complicate standard septic siting.

A public-land county first: confirm what's actually private before anything else

Lemhi County is genuinely defined by how much of it isn't privately owned. The Salmon-Challis National Forest -- which spans more than 4.2 million acres across seven Idaho counties -- has most of its Salmon-side acreage in Lemhi County, and the Bureau of Land Management's Salmon Field Office separately manages close to 500,000 additional acres in the area for grazing, mining, and multiple-use recreation. Estimates commonly cited for Lemhi County put roughly 80% of its total land area under this kind of federal administration, leaving a private-land share concentrated mainly in the valley bottoms along the Salmon, Lemhi, and Pahsimeroi rivers.

This isn't a reason to avoid Lemhi County -- it's precisely what draws many buyers here, for hunting, fishing, and genuine backcountry access from a private base. But it does mean the first real due-diligence question for a Lemhi County parcel is often not zoning, but land-ownership pattern: is this parcel a private inholding surrounded by public land, does it border a grazing allotment or a heavily used trailhead, and does neighboring public land use (seasonal hunting pressure, grazing, motorized recreation) match what you're expecting from the property. Confirm this directly with the county GIS/parcel viewer and, where relevant, the Salmon-Challis National Forest or BLM Salmon Field Office land status maps, rather than from a listing's framing alone.

River-corridor setbacks: real, specific, and central to the county's land value

Much of Lemhi County's private land value is tied directly to the Salmon and Lemhi Rivers -- for fishing access, recreational use, and simple scenic value. The county's development code addresses this directly with a specific stream-corridor standard: new development along the Salmon and Lemhi Rivers must stay at least 25 feet from the average annual high-water mark, and the county's defined stream corridor for regulatory purposes extends to cover the entire mapped special flood hazard area along with any associated wetlands and riparian areas -- meaning the actual no-build zone on a given riverside parcel can be considerably wider than the 25-foot figure suggests on its own, depending on the local floodplain mapping.

For any parcel marketed on its river frontage, get the specific buildable envelope confirmed against both this setback and current floodplain mapping before assuming where a home, driveway, or septic system can be sited -- a beautiful stretch of riverbank does not automatically mean a buildable one. Every other stream, drainage, and ravine in the county carries its own tiered setback standard, and land near Lemhi Valley streams with documented salmon or steelhead habitat may also already carry a permanent conservation easement -- see the dedicated pages below for both.

Access is a real question here, not a formality

Lemhi County's own subdivision and special-use permit process requires an applicant to document, in detail, the location, width, surface type, and name of every existing or proposed street, drive, and parking area serving a property, along with any other rights-of-way, easements, canals, or ditches -- a level of specificity that reflects how often access itself is a live question in this county, rather than an assumed given. The county also runs its own Access Permit process specifically for new road approaches onto county roads, separate from the subdivision review itself.

Given how much of Lemhi County borders or is surrounded by national forest and BLM land, a specific parcel's practical access may run through a U.S. Forest Service road, which can carry seasonal closures, maintenance limitations, or use restrictions that a county-maintained road would not, or through a private easement across a neighboring parcel rather than direct frontage on a public road. Confirm the legal basis of access -- not just whether a road currently reaches the property -- with Lemhi County Planning & Zoning/Building before finalizing a purchase, and check with the Salmon-Challis National Forest or BLM Salmon Field Office directly if access appears to cross federal land.

What we could and couldn't confirm

The roughly-80%-federal-land estimate for Lemhi County was corroborated across secondary sources during this research pass but not traced to a single, current, primary county or federal dataset breaking out exact acreage by ownership within the county's boundary -- treat it as a directional figure and confirm the ownership status of any specific parcel and its surroundings directly using county GIS or BLM/Forest Service land status records. The stream-corridor setback and access-documentation requirements are drawn directly from the county's own development code and permit application materials and are considered solidly sourced, though the development code has been amended since its 2017 adoption (most recently reflected in an August 2022 update) and should be reconfirmed as current for any specific parcel.

Verify directly with: Lemhi County Building Department (Planning & Zoning) for zoning, stream-corridor setbacks, and road access, and Eastern Idaho Public Health for septic

Who to Call Before Buying Land in Lemhi County

Lemhi County runs a combined Building Department that handles planning, zoning, building permits, and access permits under one office and phone number -- ask to be routed to the specific function you need. The Assessor and Recorder/Clerk share a single courthouse office and phone line. No independently verified, dedicated GIS-department phone contact was found separate from the county's general offices; parcel mapping is available online (search "Lemhi County parcels GIS" for the current viewer link, since the exact URL was not confirmed to a stable address during this research pass).

Planning & Zoning

Lemhi County Building Department (Planning & Zoning)

Confirming a parcel's zoning district under the 2017 Lemhi County Development Code, permitted uses, stream-corridor setback requirements, and subdivision/access-permit procedures.

Phone: (208) 756-6913Official website →