Idaho County Map: All 44 Counties
Idaho contains 44 counties spanning the Rocky Mountains, Snake River Plain, and the Panhandle. Bound by Dillon’s Rule, Idaho counties manage vast expanses of federal public forest and range lands, including Idaho County (larger than New Jersey).
Idaho at a Glance
Idaho County Map
Counties of Idaho with the state capital, Boise, marked. Hover a shape for its name or click it to jump to its row in the list below.
Printable Blank Map of Idaho with All Counties
Download the Idaho outline as SVG or PNG, or print it to PDF, in several variants: blank boundary, with counties lines, color-filled and labeled. Free to use (CC0).
Idaho County Rankings: Population & Land Area
Comparative demographic and territorial distribution across Idaho's largest administrative subdivisions based on the 2020 US Census Decennial count.
Top 10 Most Populous Counties
| # | County | Seat | Population | % State |
|---|---|---|---|---|
| 1 | Ada County | Boise | 494,961 | 26.9% |
| 2 | Canyon County | Caldwell | 231,102 | 12.6% |
| 3 | Kootenai County | Coeur d'Alene | 171,363 | 9.3% |
| 4 | Bonneville County | Idaho Falls | 123,964 | 6.7% |
| 5 | Twin Falls County | Twin Falls | 90,049 | 4.9% |
| 6 | Bannock County | Pocatello | 87,019 | 4.7% |
| 7 | Madison County | Rexburg | 52,913 | 2.9% |
| 8 | Bingham County | Blackfoot | 47,983 | 2.6% |
| 9 | Bonner County | Sandpoint | 47,103 | 2.6% |
| 10 | Nez Perce County | Lewiston | 42,091 | 2.3% |
Top 10 Largest Counties by Land Area
| # | County | Seat | Land Area | % State |
|---|---|---|---|---|
| 1 | Idaho County | Grangeville | 8,477.5 sq mi | 10.3% |
| 2 | Owyhee County | Murphy | 7,668.2 sq mi | 9.3% |
| 3 | Custer County | Challis | 4,922.2 sq mi | 6.0% |
| 4 | Lemhi County | Salmon | 4,563.7 sq mi | 5.5% |
| 5 | Valley County | Cascade | 3,665.1 sq mi | 4.4% |
| 6 | Elmore County | Mountain Home | 3,075.1 sq mi | 3.7% |
| 7 | Blaine County | Hailey | 2,637.7 sq mi | 3.2% |
| 8 | Shoshone County | Wallace | 2,637.4 sq mi | 3.2% |
| 9 | Cassia County | Burley | 2,565.6 sq mi | 3.1% |
| 10 | Clearwater County | Orofino | 2,457.3 sq mi | 3.0% |
How Local Government Operates in Idaho: 3-Member Board of County Commissioners
Governed by a 3-member Board of County Commissioners. Over 60% of Idaho’s surface area is federally owned, requiring extensive county coordination with the US Forest Service and Bureau of Land Management.
Idaho County & Federal Public Lands: Managing Frontier Wilderness
Idaho counties confront some of the highest ratios of federal land ownership in the United States.
Idaho County spans 8,485 square miles across central Idaho, bisected by the Salmon River canyon ("The River of No Return"). Over 83% of the county is federally managed by the US Forest Service, including the Frank Church–River of No Return Wilderness and Gospel-Hump Wilderness.
Because federal lands are constitutionally exempt from local property taxation, rural Idaho counties depend critically on federal Secure Rural Schools (SRS) funding and Payments in Lieu of Taxes (PILT) to maintain thousands of miles of rural logging and backcountry roads.
In Owyhee County in southwest Idaho (7,678 sq mi, only 11,913 pop), vast sagebrush steppe expanses are managed under cooperative rangeland agreements between local cattle ranchers and the Bureau of Land Management.
The Salmon River acts as a natural boundary: counties north of the Salmon River (Idaho Panhandle) observe Pacific Time, while counties to the south observe Mountain Time.
Ada County & The Treasure Valley Growth Pressures
In sharp contrast to rural timber and ranching counties, Ada and Canyon counties have experienced unprecedented suburban expansion.
Ada County (Boise) and neighboring Canyon County (Nampa/Caldwell) constitute the "Treasure Valley," home to over 725,000 residents—nearly 40% of Idaho’s total population.
Under Article XVIII of the Idaho Constitution, county commissioners manage land-use zoning in unincorporated fringe areas, facing fierce political debates over preserving historic irrigated farmland versus accommodating high-density residential subdivisions.
Ada County also features the Ada County Highway District (ACHD)—a unique single-purpose countywide independent road agency that controls all city and county streets in Ada County, completely independent of the Boise City Council.
ACHD is the only countywide highway district in the nation that oversees all municipal streets within cities like Boise and Meridian, stripping city councils of street jurisdiction.
Which county of Idaho are you in?
Use your device location to see which county of Idaho you are in right now.
List of All 44 Counties in Idaho
Every county in Idaho is listed below with its seat, 2020 Census population, land area and FIPS code. Search by name, seat or FIPS, sort any column, or export the full table as CSV.
County | Seat | 2020 Census Pop | Land Area (sq mi) | FIPS |
|---|---|---|---|---|
Ada County | Boise | 494,961 | 1,052 sq mi | 16001 |
Canyon County | Caldwell | 231,102 | 587 sq mi | 16027 |
Kootenai County | Coeur d'Alene | 171,363 | 1,238 sq mi | 16055 |
Bonneville County | Idaho Falls | 123,964 | 1,866 sq mi | 16019 |
Twin Falls County | Twin Falls | 90,049 | 1,922 sq mi | 16083 |
Bannock County | Pocatello | 87,019 | 1,113 sq mi | 16005 |
Madison County | Rexburg | 52,913 | 469 sq mi | 16065 |
Bingham County | Blackfoot | 47,983 | 2,094 sq mi | 16011 |
Bonner County | Sandpoint | 47,103 | 1,733 sq mi | 16017 |
Nez Perce County | Lewiston | 42,091 | 848 sq mi | 16069 |
Latah County | Moscow | 39,523 | 1,076 sq mi | 16057 |
Jefferson County | Rigby | 30,890 | 1,094 sq mi | 16051 |
Elmore County | Mountain Home | 28,665 | 3,075 sq mi | 16039 |
Payette County | Payette | 25,389 | 407 sq mi | 16075 |
Cassia County | Burley | 24,692 | 2,566 sq mi | 16031 |
Blaine County | Hailey | 24,278 | 2,638 sq mi | 16013 |
Jerome County | Jerome | 24,242 | 598 sq mi | 16053 |
Minidoka County | Rupert | 21,582 | 757 sq mi | 16067 |
Gem County | Emmett | 19,122 | 560 sq mi | 16045 |
Idaho County | Grangeville | 16,547 | 8,478 sq mi | 16049 |
Gooding County | Gooding | 15,601 | 729 sq mi | 16047 |
Franklin County | Preston | 14,194 | 663 sq mi | 16041 |
Fremont County | St. Anthony | 13,387 | 1,864 sq mi | 16043 |
Shoshone County | Wallace | 13,168 | 2,637 sq mi | 16079 |
Boundary County | Bonners Ferry | 12,057 | 1,269 sq mi | 16021 |
Owyhee County | Murphy | 11,915 | 7,668 sq mi | 16073 |
Valley County | Cascade | 11,744 | 3,665 sq mi | 16085 |
Teton County | Driggs | 11,631 | 449 sq mi | 16081 |
Washington County | Weiser | 10,498 | 1,453 sq mi | 16087 |
Benewah County | St. Maries | 9,531 | 777 sq mi | 16009 |
Clearwater County | Orofino | 8,728 | 2,457 sq mi | 16035 |
Lemhi County | Salmon | 7,979 | 4,564 sq mi | 16059 |
Power County | American Falls | 7,876 | 1,404 sq mi | 16077 |
Boise County | Idaho City | 7,614 | 1,900 sq mi | 16015 |
Caribou County | Soda Springs | 7,027 | 1,764 sq mi | 16029 |
Bear Lake County | Paris | 6,370 | 976 sq mi | 16007 |
Lincoln County | Shoshone | 5,127 | 1,201 sq mi | 16063 |
Oneida County | Malad City | 4,566 | 1,199 sq mi | 16071 |
Adams County | Council | 4,382 | 1,363 sq mi | 16003 |
Custer County | Challis | 4,279 | 4,922 sq mi | 16037 |
Lewis County | Nezperce | 3,526 | 479 sq mi | 16061 |
Butte County | Arco | 2,576 | 2,237 sq mi | 16023 |
Camas County | Fairfield | 1,074 | 1,074 sq mi | 16025 |
Clark County | Dubois | 789 | 1,763 sq mi | 16033 |
Neighboring States Bordering Idaho
County maps, lists and printable blank maps for the states that border Idaho:
Data Sources & FIPS Codes
Idaho uses state FIPS code 16; each county adds a three-digit code to form the five-digit FIPS (now INCITS 31) identifiers in the table. Populations are 2020 Census counts and land areas come from the Census Gazetteer. The map above is drawn from the Census Bureau's generalized 2017 cartographic boundary file (1:10,000,000), so it suits overview and printing, not parcel-level or legal boundary questions; for those, check the local assessor or GIS office.
Questions About Idaho Counties
Why are there two time zones in Idaho counties?
Northern Idaho (the 10 Panhandle counties) is economically and culturally tied to Spokane, Washington, and observes Pacific Time. Southern and eastern Idaho (34 counties) is tied to Salt Lake City and the Mountain West, observing Mountain Time. The Salmon River forms the approximate divide.
What is the largest county in Idaho by land area?
Idaho County is the largest in Idaho, covering 8,484.9 square miles. It is larger than the entire state of New Jersey.
What is the Ada County Highway District (ACHD)?
ACHD is an independent countywide government authority created by voters in 1971 that designs, builds, and maintains all public roads, traffic signals, and bridges across all cities (including Boise) and unincorporated lands in Ada County.
Related Administrative & Boundary Tools
What County Am I In?
Find your county from your device location using Census boundary polygons.
Interactive US County Map
Explore every US county on an interactive, zoomable map.
County Map with Cities
See county lines together with city and town names on one map.
Address to County Lookup
Look up which county a US street address or ZIP code is in.