O'Brien County · Iowa
ZIP code 51231
- Population
- 543
- Median income
- $105,388
- Median home
- $179,600
- Sales tax
- 6%
ZCTA residents
Household, past 12 months
Owner-occupied value
Iowa state rate
Quick answer
ZIP 51231 sits in O'Brien County, Iowa and is home to 543 people. Median household income is $105,388, the median home is worth $179,600 and median gross rent is —. 93.4% of households own their home, and purchases are taxed at 6% (Iowa state rate).
- County
- O'Brien County
- State
- Iowa (IA)
- Area codes
- Not published
- Metro area
- Outside covered metros
FIPS 19141
970 ZIPs covered
No NANPA match for this ZIP
Rate jurisdiction used for tax
The numbers for 51231
American Community Survey 2019-2023 ACS 5-year estimates for this ZCTA.
- Population
- 543ZIP 51231 residents
- Median household income
- $105,388Past 12 months, inflation adjusted
- Median home value
- $179,600Owner-occupied units
- Median gross rent
- —Rent plus utilities, monthly
- Median age
- 16.3 yrsAll residents
- Homeownership rate
- 93.4%Owner-occupied households
Sales tax in 51231
What a purchase inside this ZIP costs at checkout.
Iowa levies 6% statewide, and counties, cities and special districts inside this ZIP can add their own local rate on top. Check the county page for the local component before you quote a price.
Affordability in this ZIP
Derived from the Census medians above — indicative, not an offer.
A rent burden above 30% is the federal threshold for cost-burdened households, and a price-to-income multiple above 4× is generally considered a stretched housing market. The mortgage figure is principal and interest only — taxes, insurance and HOA dues are extra.
How 51231 compares
ZIP 51231 against the median ZIP in O'Brien County and across Iowa.
| Measure | ZIP 51231 | County median | State median | vs state |
|---|---|---|---|---|
| Median household income | $105,388 | $70,396 | $71,182 | +48% |
| Median home value | $179,600 | $146,950 | $151,550 | +19% |
| Median gross rent | — | $788 | $808 | — |
| Population | 543 | 1,142 | 935 | -42% |
Medians are computed across the 8 ZIP areas in O'Brien County and the 970 ZIP areas in Iowa.
Statewide rank
Where this ZIP places among all 970 Iowa ZIP areas.
- Income
- #64
- Home value
- #317
- Population
- #652
richer than 93% of 937 state ZIPs
above 66% of 922 state ZIPs
larger than 33% of 970 state ZIPs
Comparable ZIP codes
Iowa ZIP areas with almost the same household income.
Nearby ZIP codes
Other ZIP codes filed under O'Brien County.
ZIP 51231 questions
Common questions about this ZIP code.
- Where is ZIP code 51231?
- ZIP 51231 lies mostly in O'Brien County, Iowa. County assignment follows the largest share of land area, so a ZIP straddling a county line is filed under its dominant county.
- What sales tax do I pay in 51231?
- Iowa charges 6% statewide, plus any county, city or district rate that applies locally.
- Is 51231 expensive to live in?
- Median rent runs — a month, and the median home is worth $179,600 — +19% against the typical Iowa ZIP.
- Is a ZCTA the same as a postal ZIP code?
- Not exactly. The Census builds ZIP Code Tabulation Areas from the ZIP codes of addresses inside each census block, so a ZCTA can differ slightly from the USPS delivery route of the same number, and PO-box-only ZIPs have no ZCTA at all.
Keep going
Related pages for this area.
Sources & transparency
- US Census Bureau, ACS 2019-2023 5-year estimates — 2019-2023 ACS 5-year — population, income, housing
- Census 2020 ZCTA-to-county relationship file — County assignment by largest land-area overlap
- Iowa Department of Revenue — Sales tax rates and local add-ons
Last reviewed December 2024. Figures are published for reference and can change; verify with the source agency before filing or contracting. How we build and check this data.