Idaho County Map with All 44 Counties and Population

How to use this map

Pick a map type along the top and the map redraws. Counties colours all 44 so no two neighbours share a fill, Density shades them by people per square kilometre, Satellite swaps the flat colours for real imagery of the state, and Blank outline gives you black on white for printing. Click any county, or any row in the table, and its figures appear in the Selection panel: population, land area, density and county seat.

Names are drawn where there is room for them. With 44 counties, some are too small at this scale to label without printing one name on top of another, so the label is dropped rather than made illegible. Clicking still identifies every one, and the table lists them all.

Switch between metric and imperial with the Units control. Everything on the page follows it, including the downloads.

Where the data comes from

Boundaries and land areas come from the United States Census Bureau through the TIGERweb service, which is the same geography the Bureau uses for its own published tables. Populations are 2020 Census counts, and county seats come from the published county list.

The check that matters is the total. The 44 populations sum to 1,839,106, which is the published state figure, and the land areas sum to 214,051 square kilometres. If a set of figures for Idaho does not reach those totals, it is mixing census years or dropping units, and both are easy to do without noticing.

Aerial imagery, and how it is fitted to the map

The Satellite map type replaces the flat colours with real aerial imagery from the United States Geological Survey, taken from The National Map. Most of it comes from the National Agriculture Imagery Program, flown at one metre resolution or better, which is far sharper than a global satellite composite at this scale.

The imagery arrives as a plain latitude and longitude grid while this map is drawn in Lambert conformal conic. Laying one straight over the other would leave the coastline and the county boundaries drifting apart as you move north. So every pixel is converted back to a latitude and longitude and the matching pixel is read from the source image, which puts both in the same projection. It is then clipped to the outline, so the map shows Idaho rather than a rectangle of the surrounding region.

The imagery is public domain, as work of the United States government, so it can travel with the map when you download it. That is also why this is USGS imagery rather than the commercial layers on the big mapping sites, which are licensed from private operators and cannot be redistributed through a download button.

Two practical notes. The imagery takes a second or two to appear the first time, because it is fetched and reprojected on the spot. And although the source is flown at one metre, a whole state on one screen works out coarser than that, so you can read terrain, rivers, farmland and the edges of built up areas rather than individual buildings.

A check you can repeat on paper

Take Ada, the most populous county in the state.

The Census Bureau gives it 494,967 people and 2,725 square kilometres of land. Divide one by the other and you get 181.6 people per square kilometre.

Select Ada and the Selection panel reads 181.6. Switch to imperial and it becomes 470.4 per square mile.

Now add the 44 land areas in the table. They come to 214,051 square kilometres, and the populations to 1,839,106.

What the numbers show

4 of the 44 hold half of Idaho between them: Ada, Canyon, Kootenai, Bonneville. They cover 5.7 percent of the land, leaving the other 40 to hold the remaining half.

The densest is Ada at 181.6 people per square kilometre, then Canyon at 152.0. At the other end, Clark runs at 0.173 and Custer at 0.335. That is a spread of roughly 1,050 to one across a single state.

Idaho is the largest by area at 21,957 square kilometres and holds 16,541 people, while Payette is the smallest at 1,054. Idaho as a whole sits at 8.6 people per square kilometre, against a national figure of 36.2.

Mistakes that catch people out

Mixing census years. Populations from different vintages look identical on the page and only reveal themselves when the total misses 1,839,106. Every figure here is 2020.

Treating the drawn area as land. Every county outline includes its inland water. Bonner is the clearest case here, enclosing about 10 percent more area than its land figure. Every density on this page is computed on land area, not on the area you see drawn, and the Selection panel shows both.

Reading the colours as data. On the counties view the fills only ensure that neighbours differ, so a colour carries no meaning at all. The Density view is the one where colour maps to a number.

Related Calculators and Reference

• United States Map: all fifty states and the District of Columbia with satellite imagery, cities and rivers.
• US State Maps: every state with its capital, population, land area, density and county count.
• Texas County Map: the largest set of counties in the country at 254.
• United States Census Bureau, Geography: the source of the boundaries and land areas used here.
• The National Map viewer: the USGS browser behind the aerial imagery on this page.

County boundaries and land area: United States Census Bureau, TIGERweb, public domain. Population: 2020 Census of Population and Housing. Aerial imagery: United States Geological Survey, The National Map, public domain.