Boulder Colorado ZIP Codes

Boulder holds 11 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We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP.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 Boulder codes above are listed without a column we would have to invent.

Scope every ZIP code recorded for Boulder. 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 Boulder ZIP code begins 803. Those first three digits identify the sectional center facility that processes mail for this part of Colorado. No other Colorado community draws on the 803xx range — it belongs entirely to Boulder.

Every Colorado 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 Boulder occupies.

• 303 Area code 303
• 720 Area code 720
• 983 Area code 983

Boulder Colorado area codes in full →

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