First three digits · Wisconsin
ZIP Codes Starting with
22 ZIP codes start with 538, sorted at the Madison, WI (SCF 535) sectional center (USPS labeling list L005, effective October 1, 2026) in Wisconsin: 21 residential ZIP codes across 3 counties and 1 PO Box or single-organization code (Census 2020 ZCTAs and GeoNames postal codes, October 2026).
What do the digits 538 mean?
The first digit, 5, is one of ten national areas (Iowa, Minnesota, Montana, North Dakota, South Dakota and Wisconsin). The first three, 538, route mail to a sectional center: USPS labeling list L005 (effective October 1, 2026) sends letters for 538 to the Madison, WI (SCF 535) facility. The last two digits pick the delivery area. By residents, the largest town names among the 538 ZIP codes are Platteville, Prairie Du Chien, Lancaster, Boscobel, Fennimore and Cuba City.
The same facility sorts 4 prefixes, 195 ZIP codes in all: 535, 537, 538, 539.
Where are the 538 ZIP codes?
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries; ACS 2020-2024 5-year estimates (B19013).
All ZIP codes starting with 538
| County | ||||||
|---|---|---|---|---|---|---|
| 53801 | Bagley | Grant County | 998 | 17 | $65k | $135k |
| 53802 | Beetown | Grant County | 132 | 78 | $80k | $170k |
| 53803 | Benton | Lafayette County | 1,386 | 110 | $80k | $164k |
| 53804 | Bloomington | Grant County | 1,275 | 24 | $83k | $166k |
| 53805 | Boscobel | Grant County | 5,554 | 42 | $61k | $164k |
| 53806 | Cassville | Grant County | 1,514 | 22 | $64k | $165k |
| 53807 | Cuba City | Grant County | 4,209 | 40 | $78k | $226k |
| 53808 | Dickeyville | Grant County | 905 | 365 | $71k | $193k |
| 53809 | Fennimore | Grant County | 4,748 | 46 | $66k | $193k |
| 53810 | Glen Haven | Grant County | 389 | 10 | $76k | $168k |
| 53811 | Hazel Green | Grant County | 3,093 | 66 | $83k | $225k |
| 53812 | Kieler | Grant County | 254 | 508 | $81k | $199k |
| 53813 | Lancaster | Grant County | 6,222 | 43 | $84k | $220k |
| 53816 | Mount Hope | Grant County | 856 | 14 | $71k | $201k |
| 53817 | Patch Grove | Grant County | 227 | 599 | $49k | $150k |
| 53818 | Platteville | Grant County | 16,024 | 104 | $56k | $237k |
| 53820 | Potosi | Grant County | 2,467 | 28 | $77k | $202k |
| 53821 | Prairie Du Chien | Crawford County | 7,780 | 80 | $61k | $168k |
| 53824 | Sinsinawa | Grant County | PO Box or unique | – | – | – |
| 53825 | Stitzer | Grant County | 358 | 11 | $103k | $171k |
| 53826 | Wauzeka | Crawford County | 1,323 | 17 | $73k | $173k |
| 53827 | Woodman | Grant County | 429 | 12 | $82k | $163k |
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; GeoNames postal codes (CC BY 4.0) for codes without a residential area.