Union County ZIP Codes
South Dakota, United States · 5 codes
Union County in South Dakota has 5 ZIP codes, from 57001 to 57049, serving 5 places.
ZIP codes in Union
Frequently asked questions
What is the ZIP code of Union?
Union has 5 ZIP codes, from 57001 to 57049. The table lists the places each one serves.
How many places are listed in Union County?
5 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.