County ZIP codes · Iowa · FIPS 19023
Butler County, IA ZIP Codes
Butler County, Iowa has 18 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026), all residential. 11 of the residential ones lie mainly in Butler County and 7 mainly in a neighboring county; 13 cross the county line. Median household income ranges from $66,250 in 50601 (Ackley) to $95,969 in 50660 (New Hartford) (Census Bureau, ACS 2020-2024).
- ACS2020-24
- Census2020
Where are the ZIP codes of Butler County?
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries; ACS 2020-2024 5-year estimates (B19013).
How different are its ZIP codes?
The middle half of its ranked ZIP codes (1,000+ people living in households) report median household incomes between $67,188 and $84,076.
They carry 18 postal town names.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013).
All 18 residential ZIP codes in Butler County
11 ZIP codes lie mainly in Butler County; 7 more reach into it from a neighboring county and follow the first table.
| In this county | ||||||
|---|---|---|---|---|---|---|
| 50665 | Parkersburg | 2,693 | 27 | $76k | $218k | 64% |
| 50670 | Shell Rock | 2,270 | 41 | $85k | $172k | 97% |
| 50636 | Greene | 2,186 | 19 | $70k | $155k | 62% |
| 50619 | Clarksville | 2,150 | 26 | $84k | $163k | 100% |
| 50604 | Aplington | 1,590 | 22 | $67k | $168k | 80% |
| 50602 | Allison | 1,254 | 16 | $67k | $118k | 100% |
| 50660 | New Hartford | 1,143 | 33 | $96k | $191k | 79% |
| 50625 | Dumont | 930 | 15 | $64k | $87k | 83% |
| 50611 | Bristow | 364 | 12 | $84k | $93k | 100% |
| 50608 | Austinville | 24 | 108 | – | – | 100% |
| 50649 | Kesley | 12 | 414 | – | – | 100% |
Partly in Butler County
| In this county | ||||||
|---|---|---|---|---|---|---|
| 50605 | Aredale | 63 | 4 | $23k | $69k | 39% |
| 50666 | Plainfield | 753 | 15 | $80k | $204k | 24% |
| 50601 | Ackley | 2,299 | 16 | $66k | $127k | 18% |
| 50433 | Dougherty | 157 | 3 | $69k | $86k | 7% |
| 50658 | Nashua | 2,450 | 31 | $72k | $155k | 7% |
| 50613 | Cedar Falls | 43,867 | 344 | $79k | $271k | 4% |
| 50677 | Waverly | 12,673 | 99 | $86k | $233k | 3% |
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; county shares by land area (Census 2020 ZCTA-county relationship file).
Which ZIP codes cross the county line?
13 ZIP codes of Butler County extend into another county. A ZIP code follows mail routes, not county borders.
| ZIP | In Butler | Elsewhere |
|---|---|---|
| 50613 | 4% | Black Hawk County 81%; Grundy County 15% |
| 50677 | 3% | Bremer County 97% |
| 50665 | 64% | Grundy County 36% |
| 50658 | 7% | Chickasaw County 55%; Floyd County 34%; Bremer County 4% |
| 50601 | 18% | Franklin County 36%; Hardin County 30%; Grundy County 16% |
| 50670 | 97% | Bremer County 2% |
| 50636 | 62% | Floyd County 38% |
| 50604 | 80% | Grundy County 20% |
| 50660 | 79% | Grundy County 21% |
| 50625 | 83% | Franklin County 17% |
| 50666 | 24% | Bremer County 76% |
| 50433 | 7% | Cerro Gordo County 53%; Floyd County 21%; Franklin County 19% |
| 50605 | 39% | Franklin County 61% |
Source: U.S. Census Bureau, 2020 ZCTA-county relationship file (shares of land area).
Which first three digits do Butler County's ZIP codes use?
The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Butler County's ZIP codes use 2 prefixes: 504 and 506.
Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.