County · code 16059
Lemhi CountyIdaho
Lemhi County is a county in Idaho, with its seat at Salmon. It was created on January 9, 1869, from Idaho Territory.
- Founded1869
- County seatSalmon
- Named forFort Lemhi
- Land area4,564 sq mi + 5.5 sq mi water
- Population7,974 2020 Census
- Parcels mapped15,932 checked 16 October 2026
Where it is
Lemhi on the map of Idaho
Idaho has 44 counties and county equivalents, each with its own records office. Shapes with a page are links.
History
Formed in 1869 from Idaho County
An old deed may name a county that no longer exists, or a boundary that has since moved.
Lemhi County was created by Idaho Territory on January 9, 1869, from Idaho. The county was named after Fort Lemhi. Over the following decades, Lemhi's boundaries changed multiple times through gains and losses to neighboring counties including Oneida, Alturas, Custer, Fremont, and Idaho. When Idaho became a state on July 3, 1890, Lemhi continued as a county.
- 1869Lemhi County created Lemhi created by Idaho Territory from Idaho. · Id. Terr. Laws 1868, 5th sess., ch. 19/pp. 117-118
- 1873
- 1877
- 1881Gained territory Lemhi gained from Alturas (extinct), lost to creation of Custer.from Alturasfrom Custer· Id. Terr. Laws 1880, 11th sess., pp. 340-345
- 1890Became part of Idaho Lemhi continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. · U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156
Show all 14 changes
- 1869Lemhi County created Lemhi created by Idaho Territory from Idaho. · Id. Terr. Laws 1868, 5th sess., ch. 19/pp. 117-118
- 1873
- 1877
- 1881Gained territory Lemhi gained from Alturas (extinct), lost to creation of Custer.from Alturasfrom Custer· Id. Terr. Laws 1880, 11th sess., pp. 340-345
- 1885
- 1885Boundary clarified Lemhi boundary with Bingham clarified (no change).with Binghamno change· Id. Terr. Laws 1884, 13th sess., p. 46
- 1887Boundary clarified Lemhi boundaries redefined (no change).no change· Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 144
- 1890Became part of Idaho Lemhi continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. · U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156
- 1891Gained territory Lemhi gained from Alta (extinct) and Bingham.from Altafrom Bingham· Id. Laws 1890, 1st sess., p. 166
- 1896Lost territory Lemhi lost to Fremont. Act approved 11 March 1895, became effective through a vote in the general election of 3 November 1896. · Id. Laws 1895, 3rd sess., pp. 145-148; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-124 "Fremont Co."/p. 35
- 1899Boundary clarified Lemhi redefined (no change).no change· Id. Laws 1899, 5th sess., p. 111
- 1899Changed Lemhi's loss to Fremont on 3 November 1896 was reenacted (no change). · Id. Laws 1899, 5th sess., pp. 273-275; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-124 "Fremont Co."/p. 35
- 1903Gained territory Lemhi gained from Idaho when line between the two counties was redefined. Faulty geographic knowledge also created an overlap between Idaho and Lemhi (see Overlap Area 2). · Id. Laws 1903, 7th sess., pp. 48-49
- 1911Gained territory Lemhi gained from Idaho. Overlap between Idaho and Lemhi (see 21 February 1903) settled in favor of Idaho; Overlap Area 2 eliminated. · Id. Laws 1911, 11th sess., ch. 218/pp. 699-701
Land and parcels
What the maps cover in Lemhi
Who publishes each layer, how good it is, and when we last checked.
-
Parcels Good enough
Lot lines and tax-map numbers for 15,932 parcels from Idaho Department of Water Resources. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
checked 16 October 2026 -
Address points Missing
No public address points layer found for Lemhi County yet.
-
Buildings Reference
Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026
- Official
- from the office that keeps the record
- Good enough
- a reliable statewide or national copy
- Fallback
- a guide only; check the official record
- Missing
- nothing public found yet
People and land
Lemhi by the Census
Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.
Rules and offices
Who to ask before you build, dig or sell
Official county pages only. We link to them; we do not copy them, because they change.
Inside a city or town, permits usually come from that city rather than the county.
Records
- Clerk of court: deeds and plats
Clerk / Auditor / Recorder's Office
Permits
Zoning and code
County government
- County government
The official website of Lemhi County.
See your own lot on these maps
Open Lemhi County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.
Questions
Common questions about Lemhi County
- When was Lemhi County founded?
- Lemhi County was founded in 1869, formed from Idaho County, and named after Fort Lemhi.
- What is the county seat of Lemhi County?
- The county seat of Lemhi County is Salmon.
- Is there an online parcel map for Lemhi County?
- Yes. Idaho Department of Water Resources publishes a parcel map of 15,932 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
- Has Lemhi County's boundary or name changed?
- Lemhi County was created in 1869 from Idaho County. Since then the Atlas of Historical County Boundaries records 9 later changes, chiefly involving Idaho County, Alta County and Alturas County.
- Who issues building permits in Lemhi County?
- The county's page on building permits: County Building Permit Packet. Inside a city or town, ask that city first.
- Is my lot in a flood zone?
- We do not have flood maps for Lemhi County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby