ZIP Codes of Day County, SD

Population & People
Population & People
Total Population
5,426
Household Income
Household Income
Median Income
$73,818
Housing
Housing
Total Housing Units
3,402
Business & Economy
Business & Economy
Total Businesses
224
Employment
Employment
Employment Rate
55.87%
Education
Education
Bachelor's Degree+
22.12%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 7 ZIPs in this county.
Data Last Updated: July 1, 2026
ZIP Codes:7 ZIP Codes (7 Standard, 0 PO Box, 0 Unique) [See All]
Area Code:605
Timezone:Central (GMT -06:00)
Local Time:11:55:01 PM
Population:5,426 [See All]
FIPS:46037
Land Area:1,076 sq mi
Water Area:64 sq mi
Coordinates:45.4129, -97.5860
Quick Link:
https://www.zip-codes.com/county/sd-day.asp
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South Dakota's #35 most populous county
5,426 residents across 7 ZIPs — #35 of 82 South Dakota counties.

Standout ZIPs in this County


Most Populous
Webster · 2,621 people
48.3% of county total
Highest Income
Grenville · $106,389 median
1.4× county average
Largest Land Area
Webster · 413.0 sq mi
Spans the most ground
Fastest Growth
Webster · -4.2% (10-yr)
2,735 → 2,621 residents
Most Educated
Webster · 23.9% bachelor's+
437 of 1,826 adults 25+

Things worth knowing about Day County


5,426 residents live across 7 ZIPs covering 1,076 sq mi, served by 7 distinct USPS-recognized cities.

Population moved from 5,639 to 5,426 from 2014 to 2024 — a -3.8% change. 4 ZIPs gained residents, 3 lost.

The county's wealthiest ZIP 57239 (Grenville, $106,389 median) and poorest ZIP 57273 (Waubay, $48,167) are 13.7 miles apart — a 2.2× income gap across local geography.

Median home values vary 3.9× across this county — from $95,700 in 57219 (Bristol) to $377,300 in 57239 (Grenville).

Density varies across the county — from 1 people/sq mi in 57422 (Andover) to 8 in 57239 (Grenville).

Educational attainment ranges from 10.5% bachelor's+ in 57219 (Bristol) to 34.9% in 57239 (Grenville) — the breadth of educational profiles across the area.

Within South Dakota, this is the #35 most populous of 82 counties and ranks #44 for median household income .

Weighted by population, the typical household earns about $66,247 across the county — reflecting what a typical resident sees, not a simple ZIP average.

22.1% of adults age 25+ hold a bachelor's degree or higher (853 of 3,856 reporting).

7 Standard delivery, 0 PO Box only, 0 single-entity Unique ZIPs serve this county.

Stories about Day County


Big & sparse

A frontier county — vast land area with only a few residents per square mile. Daily life looks very different here than in the country's denser counties.

Total area
1,076
square miles
Avg density
5.0
people per sq mi
Population
5,426
across 7 ZIPs
Webster
413.0 sq mi
2,621 residents
Waubay
181.7 sq mi
1,165 residents
Bristol
145.7 sq mi
552 residents

All ZIP Codes in Day County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
57274WebsterStandard2,621$68,083413.0-4.2%
57273WaubayStandard1,165$48,167181.7-11.7%
57219BristolStandard552$51,900145.72.8%
57239GrenvilleStandard358$106,38945.223.0%
57468PierpontStandard279$76,25088.518.2%
57261RoslynStandard277$77,81373.19.5%
57422AndoverStandard174$88,125129.0-34.8%

Adjacent & Nearby Counties