Residential delivery area · Iowa
ZIP Code 51031: Le Mars, IA
ZIP code 51031 uses the postal name Le Mars, Iowa and lies mostly in Plymouth County (99% of its land) with the rest in Sioux County (Census 2020 ZIP-county file). About 13,000 people live there (Census Bureau, ACS 2020-2024). Median household income is $76,525 (Census Bureau, ACS 2020-2024). By Census place, its land lies in Le Mars (4%), Struble (under 1%) and Craig (0%); 96% is outside any Census place.
- ACS2020-24
- Census2020
- FHFA2025
- ZBP2023
- IRS2022
- Town
- Le Mars · its only residential ZIP
- County
- Plymouth County (99%); Sioux County (1%)
- Census places
- Le Mars (4%); Struble (under 1%); Craig (0%)
- Micro area
- Le Mars, IA
- House district
- IA-4 119th Congress
- State
- Iowa
- Time zone
- Central
- Land area
- 234.1 sq mi · 55 people per sq mi
Where is ZIP code 51031?
51031 centers on 42.803°, -96.186° and covers 234.1 square miles of land plus 0.0 of water. It borders 11 ZIP codes: 51008, 51045, 51038, 51036, 51050, 51024, 51027, 51041, 51003, 51028 and more.
The map draws ZIP code areas only. For the streets inside 51031, 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 51031 compare with the rest of Plymouth County?
| Measure | 51031 | In Plymouth County | In IA |
|---|---|---|---|
| People (ACS 2020-2024) | 12,808 | 1st of 14 | 64th of 970 |
| Median household income | $77k | 7th of 8 | 195th of 396 |
| Median home value | $223k | 3rd of 9 | 134th of 423 |
Its median household income is higher than in 57% of U.S. residential ZIP codes, and it is denser than 44% 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 51031?
The 2020 Census counted 12,960 people in 51031; the ACS, which samples households over 2020-2024, estimates 12,808. Between the 2010 and 2020 censuses its population grew 5.1% (its boundary stayed at least 90% the same).
- People, ACS 2020-2024
- 12,808
- 2020 Census count
- 12,960+5.1% since 2010 (12,336)
- Households
- 5,217
- Median age
- 39.0
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 51031?
Of the 12,808 people the ACS estimates in 51031, 25.5% are under 18 and 17.2% are 65 or older. The largest group by race and Hispanic origin is White (not Hispanic) (83.5%).
- Under 1825.5%
- 18 to 6457.3%
- 65 and older17.2%
- White, not Hispanic83.5%
- Hispanic or Latino9.5%
- Black, not Hispanic4.6%
- Other or two or more2.2%
- Asian, not Hispanic0.1%
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 51031 earn?
Median household income is $76,525 (ACS 2020-2024), the 7th highest of the 8 ranked ZIP codes in Plymouth County. It is not measurably different from 2015-2019 ($80,882 in 2024 dollars): the change is within the surveys' margins of error.
- Median household income
- $76,525
- Income per person
- $38,599
- Below the poverty line
- 8.3%
- Unemployed (of the labor force)
- 2.6%
- Adults 25+ with a bachelor's degree
- 21.9%
- Adjusted gross income per tax return, 2022
- $92,3756,220 returns; wages 58% 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 51031?
FHFA's house price index for 51031, built from repeat sales and appraisals of the same homes, rose 70% from 2015 to 2025 and rose 44% from 2020 to 2025, and moved +4.4% in 2025.
- Median home value (owners' estimate)
- $222,800
- Median gross rent
- $928
- Homes owned by their occupants
- 65.1%
- Housing units
- 5,461
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 51031?
383 business establishments had a location in this ZIP code in 2023, 14 fewer than in 2018; the most are in retail trade (ZIP Code Business Patterns).
- Retail trade47
- Other services (except public administration)46
- Construction44
- Health care and social assistance36
- Transportation and warehousing33
- Accommodation and food services33
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 51031?
| ZIP | Town | People | Household income | Distance |
|---|---|---|---|---|
| 51008 | Brunsville | 210 | $45k | 4.1 mi |
| 51045 | Oyens | 66 | $114k | 6.6 mi |
| 51038 | Merrill | 1,449 | $96k | 9.6 mi |
| 51036 | Maurice | 445 | $123k | 11.5 mi |
| 51050 | Remsen | 2,962 | $93k | 12.1 mi |
| 51024 | Hinton | 2,081 | $114k | 12.8 mi |
| 51027 | Ireton | 1,280 | $101k | 13.3 mi |
| 51041 | Orange City | 7,324 | $84k | 16.3 mi |
| 51003 | Alton | 1,938 | $101k | 16.4 mi |
| 51028 | Kingsley | 2,191 | $78k | 17.5 mi |
| 51001 | Akron | 2,342 | $75k | 18.4 mi |
Source: PlainZIP from the Census 2020 ZCTA boundaries (shared edges) and internal points; figures ACS 2020-2024.