| ZIP Codes: | 4 ZIP Codes (2 Standard, 0 PO Box, 2 Unique) [See All] |
| Area Codes: | 208 / 986 |
| Timezone: | Mountain (GMT -07:00) |
| Local Time: | 2:11:58 PM |
| Population: | 54,842 [See All] |
| FIPS: | 16065 |
| CBSA: | Rexburg, ID |
| Land Area: | 240 sq mi |
| Water Area: | 3 sq mi |
| Coordinates: | 43.8233, -111.7750 |
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54,842 residents live across 4 ZIPs covering 240 sq mi, served by 2 distinct USPS-recognized cities.
Population moved from 38,892 to 54,842 from 2014 to 2024 — a +41.0% change. 2 ZIPs gained residents, 1 lost.
The county's wealthiest ZIP 83448 (Sugar City, $76,000 median) and poorest ZIP 83440 (Rexburg, $58,159) are 7.2 miles apart — a 1.3× income gap across local geography.
Median home values vary 1.1× across this county — from $381,900 in 83448 (Sugar City) to $419,300 in 83440 (Rexburg).
Density varies 2× across the county — from 100 people/sq mi in 83448 (Sugar City) to 250 in 83440 (Rexburg).
Educational attainment ranges from 40.9% bachelor's+ in 83440 (Rexburg) to 46.6% in 83448 (Sugar City) — the breadth of educational profiles across the area.
Within Idaho, this is the #7 most populous of 46 counties and ranks #27 for median household income with the #1 fastest decade growth .
On the national stage, Madison County is and #27 for decade growth .
Weighted by population, the typical household earns about $59,255 across the county — reflecting what a typical resident sees, not a simple ZIP average.
41.5% of adults age 25+ hold a bachelor's degree or higher (7,702 of 18,572 reporting).
2 Standard delivery, 0 PO Box only, 2 single-entity Unique ZIPs serve this county.
Madison County grew 41.0% over the past decade — concentrated in 2 high-growth ZIPs:
One ZIP holds the majority of this county's population — a sign of a county built around a single city or town.