County ZIP codes · Illinois · FIPS 17131
Mercer County, IL ZIP Codes
Mercer County, Illinois has 17 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026), all residential. 13 of the residential ones lie mainly in Mercer County and 4 mainly in a neighboring county; 11 cross the county line. Median household income ranges from $56,875 in 61465 (New Windsor) to $102,639 in 61281 (Sherrard) (Census Bureau, ACS 2020-2024).
- ACS2020-24
- Census2020
Where are the ZIP codes of Mercer 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 $70,991 and $86,250.
They carry 17 postal town names.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013).
All 17 residential ZIP codes in Mercer County
13 ZIP codes lie mainly in Mercer County; 4 more reach into it from a neighboring county and follow the first table.
| In this county | ||||||
|---|---|---|---|---|---|---|
| 61231 | Aledo | 4,962 | 32 | $71k | $148k | 100% |
| 61281 | Sherrard | 2,520 | 63 | $103k | $224k | 83% |
| 61272 | New Boston | 1,437 | 16 | $64k | $146k | 97% |
| 61412 | Alexis | 1,392 | 17 | $82k | $118k | 55% |
| 61486 | Viola | 1,330 | 31 | $79k | $135k | 100% |
| 61465 | New Windsor | 1,192 | 29 | $57k | $127k | 84% |
| 61279 | Reynolds | 1,015 | 26 | $88k | $162k | 53% |
| 61260 | Joy | 737 | 13 | $42k | $97k | 100% |
| 61263 | Matherville | 657 | 481 | $87k | $135k | 100% |
| 61476 | Seaton | 551 | 12 | $88k | $123k | 72% |
| 61442 | Keithsburg | 504 | 18 | $49k | $67k | 79% |
| 61466 | North Henderson | 263 | 11 | $74k | $90k | 100% |
| 61276 | Preemption | 88 | 260 | $88k | $89k | 100% |
Partly in Mercer County
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?
11 ZIP codes of Mercer County extend into another county. A ZIP code follows mail routes, not county borders.
| ZIP | In Mercer | Elsewhere |
|---|---|---|
| 61264 | 2% | Rock Island County 98% |
| 61281 | 83% | Rock Island County 17% |
| 61272 | 97% | Rock Island County 3% |
| 61412 | 55% | Warren County 45% |
| 61262 | 6% | Henry County 94% |
| 61465 | 84% | Henry County 16% |
| 61259 | 3% | Rock Island County 97% |
| 61279 | 53% | Rock Island County 47% |
| 61476 | 72% | Henderson County 28% |
| 61442 | 79% | Henderson County 21% |
| 61472 | 1% | Knox County 99% |
Source: U.S. Census Bureau, 2020 ZCTA-county relationship file (shares of land area).
Which first three digits do Mercer County's ZIP codes use?
The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Mercer County's ZIP codes use 2 prefixes: 612 and 614.
Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.