ZIP Codes of Harding County, SD

Population & People
Population & People
Total Population
1,115
Household Income
Household Income
Median Income
$56,550
Housing
Housing
Total Housing Units
748
Business & Economy
Business & Economy
Total Businesses
21
Employment
Employment
Employment Rate
54.78%
Education
Education
Bachelor's Degree+
20.85%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 5 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:6 ZIP Codes (5 Standard, 1 PO Box, 0 Unique) [See All]
Area Code:406
Timezone:Mountain (GMT -07:00)
Local Time:2:13:42 PM
Population:1,115 [See All]
FIPS:30011
Land Area:2,407 sq mi
Water Area:4 sq mi
Coordinates:45.4508, -104.5590
Quick Link:
https://www.zip-codes.com/county/sd-harding.asp
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Among South Dakota's 5 oldest counties
Median age 57.9.

Standout ZIPs in this County


Most Populous
Buffalo · 518 people
52.1% of county total
Highest Income
Reva · $94,559 median
1.2× county average
Largest Land Area
Buffalo · 1,371.3 sq mi
Spans the most ground
Fastest Growth
— growth not calculable
Most Educated
— no education data

Things worth knowing about Harding County


994 residents live across 6 ZIPs covering 2,407 sq mi, served by 6 distinct USPS-recognized cities.

Population moved from 1,116 to 994 from 2014 to 2024 — a -10.9% change. 2 ZIPs gained residents, 3 lost (and 1 held flat).

The county's wealthiest ZIP 57651 (Reva, $94,559 median) and poorest ZIP 57724 (Camp Crook, $61,146) are 47.0 miles apart — a 1.5× income gap across local geography.

Median home values vary 1.4× across this county — from $157,000 in 57720 (Buffalo) to $212,500 in 57651 (Reva).

Density varies across the county — from 0 people/sq mi in 57755 (Ludlow) to 1 in 57724 (Camp Crook).

Educational attainment ranges from 25.0% bachelor's+ in 57720 (Buffalo) to 40.1% in 57724 (Camp Crook) — the breadth of educational profiles across the area.

Within South Dakota, this is the #52 most populous of 56 counties and ranks #48 for median household income .

Weighted by population, the typical household earns about $77,914 across the county — reflecting what a typical resident sees, not a simple ZIP average.

30.2% of adults age 25+ hold a bachelor's degree or higher (222 of 734 reporting).

5 Standard delivery, 1 PO Box only, 0 single-entity Unique ZIPs serve this county.

Stories about Harding 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
2,407
square miles
Avg density
0.4
people per sq mi
Population
994
across 6 ZIPs
Buffalo
1,371.3 sq mi
518 residents
Reva
379.7 sq mi
191 residents
Ludlow
287.4 sq mi
101 residents

All ZIP Codes in Harding County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
57720BuffaloStandard518$79,0911,371.3-9.6%
57651RevaStandard191$94,559379.735.5%
57724Camp CrookStandard167$61,146206.6-39.7%
57755LudlowStandard101$68,125287.413.5%
57650RalphStandard17136.3-52.8%
57776RedigPO Box025.8

Adjacent & Nearby Counties