O'Brien County ZIP Codes
Iowa, United States · 8 codes
O'Brien County in Iowa has 8 ZIP codes, from 51009 to 51346, serving 8 places.
ZIP codes in O'Brien
Frequently asked questions
What is the ZIP code of O'Brien?
O'Brien has 8 ZIP codes, from 51009 to 51346. The table lists the places each one serves.
How many places are listed in O'Brien County?
8 places.
Source: GeoNames postal codes (CC BY 4.0), geonames.org, retrieved 2026-10-22. Place coordinates are approximate. Check with the national postal service before sending anything valuable.