Elmore County area

Population and density of Elmore County

The Census Bureau estimates that 29,465 people lived in Elmore County on July 1, 2025. That ranks #1,503 of 3,222 county equivalents nationally and #13 of 44 in Idaho. Since the April 1, 2020 estimates base of 28,665, the population has grown by 800 (+2.8%), compared with +10.4% for Idaho as a whole.

With 3,075.1 square miles of land, that is 9.6 people per square mile (3.7 per km²), placing Elmore County #2,659 nationally for density and #24 in Idaho. The median county equivalent has 47 people per square mile; the Idaho median is 10. Put another way, there are about 67 acres of land per resident.

U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.

Cities and towns in Elmore County

2 incorporated places lie at least partly in Elmore County. Together they are home to 18,035 people (61.2%); the other 11,430 (38.8%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Mountain Home city, with 16,779 residents in the county. Among places with at least 1,000 residents in 2020, Mountain Home city grew fastest since then (+4.6%).

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Elmore County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

Elmore County is a central county of the Mountain Home, ID Micropolitan Statistical Area. Elmore County is the area’s only county equivalent, so the micro area has the same 3,075.1 square miles of land. By combined land it ranks #48 of 542 micropolitan areas, and #443 by population. It belongs to the Boise City-Mountain Home-Ontario, ID-OR Combined Statistical Area.

ZIP codes

8 ZIP Code Tabulation Areas have land in Elmore County; 6 of them have most of their land inside the county, and the others mainly cover neighboring areas.

8333783623836248362783633836478364883716

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Elmore County

Elmore County shares a land border with 8 county equivalents. It has more land than 6 of them. The largest neighbor is Owyhee County (7,668.2 mi²) and the smallest is Gooding County (729.3 mi²). Together with its neighbors, Elmore County forms a block of 24,980.1 mi² of land, of which it holds 12.3%.

How big is Elmore County compared with U.S. states?

Elmore County has more land than 2 of the 50 states. It is about 1.6 times the land area of Delaware (1,948.6 mi²), while Connecticut, the next larger state, has 1.6 times as much land (4,842.5 mi²). Idaho’s county land could hold about 27 areas the size of Elmore County.

Another way to picture it: the same land area would fill a square about 55.5 miles (89.2 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.

State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.

What stands out about Elmore County?

Elmore County has more land than 3,055 of the other 3,221 county equivalents in the dataset.

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Elmore County at #180 nationally by total area, 13 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.

Its water share is 0.9%, compared with a national county-equivalent median of 1.2% — 0.3 percentage points lower. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Elmore County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.