Union County, SD ZIP codes
Union County, SD has 4 ZIP codes, in 4 towns: 57049, 57025, 57038 and 57001. 3 more cross into it from neighbouring counties: 57004, 51023 and 51001.
The county seat is Elk Point.
- ZIP codes
- 4
- Partly in it
- 3 more
- Towns
- 4
- County seat
- Elk Point
- County FIPS
46127- State
- South Dakota
- Population
- 17,081
- Median household income
- $89,636
- Land area
- 461 sq mi
- Metro area
- Sioux City
Union County ZIP codes by town
Each ZIP code is listed under the county most of its land lies in and the town the Postal Service names it for; a ZIP code's own page shows exactly how it is split.
ZIP codes partly in Union County
These ZIP codes lie mostly in a neighbouring county but each cover a twentieth or more of Union County.
- 51001 Akron · mostly in Plymouth County
- 51023 Hawarden · mostly in Sioux County
- 57004 Beresford · mostly in Lincoln County
Map of Union County ZIP codes
The ZIP codes of Union County, shaded. Outlines are Census ZIP Code Tabulation Areas (2020), which approximate the mail routes; PO-box and single-address codes have no area and are not drawn. Click any area to open its ZIP code.
Union County in numbers
About 17,081 people live in Union County, in 7,310 households, the 13th most populous of South Dakota's 66 counties. The median household income is $89,636 a year, 19% above the South Dakota median of $75,081 (US: $80,734). The median owner-occupied home is valued at $301,100 (17% above the South Dakota median), and median gross rent is $1,069 a month. The median age is 41.5; 37.0% of adults 25 and over hold a bachelor's degree or higher (31.9% across South Dakota); the average commute takes 18 minutes.
| Population | 17,081 |
|---|---|
| Households | 7,310 |
| Median age | 41.5 |
| Median household income | $89,636 |
| Median home value | $301,100 |
| Median gross rent | $1,069 |
| Bachelor's degree or higher | 37.0% |
| Mean commute | 17.7 min |
| Population density | 37 / sq mi |
U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates. Survey estimates carry margins of error, wider for small places. Sources and methods.
Largest towns in Union County
| Town | ZIP codes | Population |
|---|---|---|
| North Sioux City | 1 | 3,045 |
| Elk Point | 1 | 2,537 |
| Alcester | 1 | 989 |
| Jefferson | 1 | 554 |
Population of the census place of that name where there is one, otherwise of the ZIP codes the Postal Service addresses by it. A town's ZIP codes can reach past the county line.
Neighbouring counties
Counties that share a ZIP code with Union County.
Not sure you are in Union County? What county am I in? answers from your location, near a county line included.
Every ZIP code in Union County, with figures
| ZIP | City | Type | Population | Median income | Median home |
|---|---|---|---|---|---|
57001 | Alcester , SD | Standard | 1,540 | $69,531 | $177,400 |
57025 | Elk Point , SD | Standard | 3,120 | $94,839 | $237,900 |
57038 | Jefferson , SD | Standard | 1,796 | $106,250 | $332,300 |
57049 | North Sioux City , SD | Standard | 7,962 | $93,134 | $432,100 |
Cite this page
zipcodes.pro. “Union County ZIP codes.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/state/sd/county/union
Underlying data is public domain or openly licensed — sources, vintages and licences.