Janesville Wisconsin ZIP Codes

Janesville holds 4 ZIP codes, all inside one county and one postal prefix.

We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP. USPS delivery-type products are licensed, and no clean-rights source maps ZIP codes to neighbourhoods — so the Janesville codes above are listed without a column we would have to invent.

Scope every ZIP code recorded for Janesville. Source GeoNames US postal codes (2026-07 postal dump) and Census 2024 county Gazetteer (2024 Gazetteer). Updated 15 July 2026. ZIP codes are delivery-route groupings, not areas; the boundaries implied by any ZIP map are approximations.

Every Janesville ZIP code begins 535. Those first three digits identify the sectional center facility that processes mail for this part of Wisconsin. Statewide that range covers 87 ZIP codes, so Janesville accounts for 5% of it.

Every Wisconsin ZIP prefix and the region it covers →

ZIP codes and area codes are separate systems — one routes mail, the other routes calls — and they do not share boundaries. The codes below serve the same ground Janesville occupies.

• 353 Area code 353
• 608 Area code 608

Janesville Wisconsin area codes in full →

Straight-line distance between place reference points, not driving distance.