Union County, South Dakota ZIP codes
4 ZIP codes are in Union County, plus 5 that cross in from neighboring counties. It's part of the Sioux City, IA-NE-SD metro area.
- ZIP codes
- 4
- Population in these ZIPs
- 14,418
- Avg. median income
- $92,600population-weighted
- Cities & towns
- 4
Click anywhere on the map to see which ZIP code it's in.
ZIP codes in Union County
| ZIP code | City | Population | Median income | Typical home value |
|---|---|---|---|---|
| 57001 | Alcester | 1,540 | $69,531 | $288,800 |
| 57025 | Elk Point | 3,120 | $94,839 | $298,200 |
| 57038 | Jefferson | 1,796 | $106,250 | $387,100 |
| 57049 | North Sioux City | 7,962 | $93,134 | $422,200 |
ZIP codes partly in Union County
These ZIP codes are mostly in a neighboring county but cover part of Union County.
| ZIP code | City | State | County | Population | Median income | Typical home value |
|---|---|---|---|---|---|---|
| 51001 | Akron | IA | Plymouth County | 2,342 | $75,404 | $235,700 |
| 51023 | Hawarden | IA | Sioux County | 3,473 | $80,357 | $187,300 |
| 57004 | Beresford | SD | Lincoln County | 3,834 | $88,750 | $323,900 |
| 57010 | Burbank | SD | Clay County | 755 | $93,611 | $369,200 |
| 57034 | Hudson | SD | Lincoln County | 661 | $89,688 | $194,300 |
Population and median household income: ACS 2020–2024 5-year estimates. Typical home value: Zillow Home Value Index (September 2026) where available, otherwise the ACS median owner-reported value. "PO Box" marks ZIP codes with no delivery area of their own. Methodology
Cities and towns in Union County
Nearby counties
Frequently asked questions
How many ZIP codes are in Union County, South Dakota?
4 ZIP codes are mainly in Union County, and 5 more ZIP codes from neighboring areas reach partly into it.
What cities are in Union County?
ZIP codes in Union County use the city names Alcester, Elk Point, Jefferson and North Sioux City.
What metro area is Union County in?
Union County is part of the Sioux City, IA-NE-SD metropolitan statistical area.