Residential delivery area · Iowa
ZIP Code 51566: Red Oak, IA
ZIP code 51566 uses the postal name Red Oak, Iowa and lies mostly in Montgomery County (91% of its land), reaching into Page County and Pottawattamie County (Census 2020 ZIP-county file). About 7,000 people live there (Census Bureau, ACS 2020-2024). Median household income is $56,637 (Census Bureau, ACS 2020-2024). By Census place, its land lies in Red Oak (2%) and Coburg (under 1%); 98% is outside any Census place.
- ACS2020-24
- Census2020
- FHFA2025
- ZBP2023
- IRS2022
- Town
- Red Oak · its only residential ZIP
- County
- Montgomery County (91%); Page County (7%); Pottawattamie County (2%)
- Census places
- Red Oak (2%); Coburg (under 1%)
- House districts
- IA-3 (98%), IA-4 (2%) 119th Congress, by share of land
- State
- Iowa
- Time zone
- Central
- Land area
- 176.4 sq mi · 40 people per sq mi
- PO Box ZIPs
- 51591 also use the name Red Oak
Where is ZIP code 51566?
51566 centers on 41.015°, -95.230° and covers 176.4 square miles of land plus 0.6 of water. It borders 8 ZIP codes: 51573, 51533, 51532, 51638, 51541, 50864, 51535, 51632.
The map draws ZIP code areas only. For the streets inside 51566, open its center on OpenStreetMap.
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries and the 2023 Gazetteer (2020 ZCTAs); ZIP-to-county shares, Census places and House districts (119th Congress) from the Census 2020 relationship files (shares of land); metro area from the OMB delineation (July 2023); town name and time zone from simplemaps US ZIP Codes (CC BY 4.0).
How does 51566 compare with the rest of Montgomery County?
| Measure | 51566 | In Montgomery County | In IA |
|---|---|---|---|
| People (ACS 2020-2024) | 7,010 | 1st of 10 | 111th of 970 |
| Median household income | $57k | 3rd of 3 | 377th of 396 |
| Median home value | $134k | 1st of 3 | 353rd of 423 |
Its median household income is higher than in 24% of U.S. residential ZIP codes, and it is denser than 38% of all U.S. residential ZIP codes. ZIP codes at the ACS caps ($250,000 or more for household income, $2,000,000 or more for home value) share the top rank.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01003, B19013, B25077); ranks by PlainZIP over residential ZIP codes (ZCTAs).
How many people live in 51566?
The 2020 Census counted 6,772 people in 51566; the ACS, which samples households over 2020-2024, estimates 7,010. Between the 2010 and 2020 censuses its population fell 3.7% (its boundary stayed at least 90% the same).
- People, ACS 2020-2024
- 7,010
- 2020 Census count
- 6,772−3.7% since 2010 (7,035)
- Households
- 3,128
- Median age
- 42.1
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01003, B01002, B11001); 2020 Census (DHC P1); 2010 Census (SF1 P1).
Who lives in 51566?
Of the 7,010 people the ACS estimates in 51566, 23.6% are under 18 and 20.7% are 65 or older. The largest group by race and Hispanic origin is White (not Hispanic) (90.7%).
- Under 1823.6%
- 18 to 6455.8%
- 65 and older20.7%
- White, not Hispanic90.7%
- Other or two or more4.9%
- Black, not Hispanic2.4%
- Asian, not Hispanic1.6%
- Hispanic or Latino0.5%
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01001 age by sex, B03002 Hispanic or Latino origin by race); shares of the estimated population, small ZIP codes carry wide margins.
What do households in 51566 earn?
Median household income is $56,637 (ACS 2020-2024), the 3rd highest of the 3 ranked ZIP codes in Montgomery County. It is not measurably different from 2015-2019 ($58,666 in 2024 dollars): the change is within the surveys' margins of error.
- Median household income
- $56,637±$11,260
- Income per person
- $37,850
- Below the poverty line
- 17.2%
- Unemployed (of the labor force)
- 3.2%
- Adults 25+ with a bachelor's degree
- 20.9%
- Adjusted gross income per tax return, 2022
- $65,6333,070 returns; wages 62% of AGI (IRS)
Source: U.S. Census Bureau, ACS 2020-2024 and 2015-2019 5-year estimates (B19013, B19301, B17001, B23025, B15003; 2015-2019 dollars converted with the BLS CPI-U, 1.22699); IRS Statistics of Income, ZIP code data, tax year 2022 (adjusted gross income per return, filed under the address on the return).
What are homes worth in 51566?
FHFA's house price index for 51566, built from repeat sales and appraisals of the same homes, rose 89% from 2015 to 2025 and rose 78% from 2020 to 2025, and moved +18.8% in 2025.
- Median home value (owners' estimate)
- $134,200
- Median gross rent
- $829
- Homes owned by their occupants
- 63.7%
- Housing units
- 3,432
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B25077, B25064, B25003, B25001); FHFA House Price Index, annual five-digit ZIP, updated 2026-03-31.
What businesses are in 51566?
207 business establishments had a location in this ZIP code in 2023, 9 fewer than in 2018; the most are in retail trade (ZIP Code Business Patterns).
- Retail trade30
- Health care and social assistance28
- Construction25
- Other services (except public administration)23
- Accommodation and food services19
- Finance and insurance15
Source: U.S. Census Bureau, ZIP Code Business Patterns 2023 and 2018 (establishments with paid employees, by the business's ZIP code).
Which ZIP codes are next to 51566?
| ZIP | Town | People | Household income | Distance |
|---|---|---|---|---|
| 51573 | Stanton | 979 | $86k | 7.5 mi |
| 51533 | Emerson | 844 | $69k | 7.9 mi |
| 51532 | Elliott | 644 | $65k | 10.6 mi |
| 51638 | Essex | 1,258 | $59k | 12.4 mi |
| 51541 | Henderson | 273 | $92k | 12.9 mi |
| 50864 | Villisca | 1,662 | $70k | 13.5 mi |
| 51535 | Griswold | 1,697 | $76k | 15.6 mi |
| 51632 | Clarinda | 6,624 | $55k | 20.9 mi |
| 51645 | Imogene | 419 | $218k | 13.6 mi (near) |
| 51540 | Hastings | 372 | $84k | 14.0 mi (near) |
Source: PlainZIP from the Census 2020 ZCTA boundaries (shared edges) and internal points; figures ACS 2020-2024.
Which other ZIP codes use the name Red Oak?
1 more ZIP code carries the postal name Red Oak, IA without a residential delivery area: PO boxes at the post office, or a single organization with its own ZIP code. The Census Bureau publishes no figures for it.
| ZIP | County |
|---|---|
| 51591 | Montgomery County |
Source: GeoNames postal codes (CC BY 4.0), downloaded 2026-10-09; a ZIP code with no Census ZCTA has no residential delivery area.