| ZIP Codes: | 10 ZIP Codes (10 Standard, 0 PO Box, 0 Unique) [See All] |
| Area Codes: | 319 / 563 |
| Timezone: | Central (GMT -06:00) |
| Local Time: | 2:11:53 PM |
| Population: | 20,228 [See All] |
| FIPS: | 19105 |
| CBSA: | Cedar Rapids, IA |
| Land Area: | 522 sq mi |
| Water Area: | 1 sq mi |
| Coordinates: | 42.0832, -91.1411 |
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20,228 residents live across 10 ZIPs covering 522 sq mi, served by 10 distinct USPS-recognized cities.
Population moved from 19,474 to 20,215 from 2014 to 2024 — a +3.8% change. 4 ZIPs gained residents, 5 lost.
The county's wealthiest ZIP 52212 (Center Junction, $110,461 median) and poorest ZIP 52323 (Oxford Junction, $41,425) are 10.8 miles apart — a 2.7× income gap across local geography.
Median home values vary 2.6× across this county — from $85,800 in 52323 (Oxford Junction) to $221,500 in 52205 (Anamosa).
Density varies 7× across the county — from 10 people/sq mi in 52321 (Onslow) to 71 in 52205 (Anamosa).
Educational attainment ranges from 3.5% bachelor's+ in 52323 (Oxford Junction) to 30.3% in 52212 (Center Junction) — the breadth of educational profiles across the area.
Within Iowa, this is the #33 most populous of 99 counties and ranks #54 for median household income .
Weighted by population, the typical household earns about $76,805 across the county — reflecting what a typical resident sees, not a simple ZIP average.
21.5% of adults age 25+ hold a bachelor's degree or higher (3,170 of 14,740 reporting).
10 Standard delivery, 0 PO Box only, 0 single-entity Unique ZIPs serve this county.
A frontier county — vast land area with only a few residents per square mile. Daily life looks very different here than in the country's denser counties.
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 52205 | Anamosa | Standard | 8,627 | $72,500 | 122.1 | -0.1% |
| 52310 | Monticello | Standard | 6,450 | $86,080 | 150.9 | -0.2% |
| 52320 | Olin | Standard | 1,425 | $62,222 | 57.0 | 28.7% |
| 52323 | Oxford Junction | Standard | 942 | $41,425 | 48.4 | -17.4% |
| 52305 | Martelle | Standard | 913 | $94,452 | 28.8 | 101.5% |
| 52362 | Wyoming | Standard | 816 | $72,583 | 50.9 | 10.9% |
| 52212 | Center Junction | Standard | 601 | $110,461 | 22.2 | 199.0% |
| 52321 | Onslow | Standard | 395 | $77,708 | 39.7 | -31.9% |
| 52312 | Morley | Standard | 46 | $37,188 | 0.1 | -70.3% |
| 52252 | Langworthy | Standard | 13 | — | 1.4 | — |