ZIP Codes of Harper County, OK

Population & People
Population & People
Total Population
3,463
Household Income
Household Income
Median Income
$63,528
Housing
Housing
Total Housing Units
1,909
Business & Economy
Business & Economy
Total Businesses
91
Employment
Employment
Employment Rate
57.17%
Education
Education
Bachelor's Degree+
29.94%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 4 ZIPs in this county.
Data Last Updated: July 1, 2026
ZIP Codes:4 ZIP Codes (4 Standard, 0 PO Box, 0 Unique) [See All]
Area Code:580
Timezone:Central (GMT -06:00)
Local Time:11:54:44 PM
Population:3,463 [See All]
FIPS:40059
Land Area:1,328 sq mi
Water Area:2 sq mi
Coordinates:36.7257, -99.7941
Quick Link:
https://www.zip-codes.com/county/ok-harper.asp
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Notable population decline
Lost 12.7% of residents since 2014.
Striking education divide
Bachelor's share spans 19.8% to 61.6% — a 42-point gap.

Standout ZIPs in this County


Most Populous
Laverne · 1,555 people
44.9% of county total
Highest Income
Buffalo · $72,500 median
1.1× county average
Largest Land Area
Laverne · 586.5 sq mi
Spans the most ground
Fastest Growth
Buffalo · -13.3% (10-yr)
1,781 → 1,544 residents
Most Educated
Laverne · 31.6% bachelor's+
356 of 1,127 adults 25+

Things worth knowing about Harper County


3,463 residents live across 4 ZIPs covering 1,328 sq mi, served by 4 distinct USPS-recognized cities.

Population moved from 3,966 to 3,463 from 2014 to 2024 — a -12.7% change. 2 ZIPs gained residents, 2 lost.

The county's wealthiest ZIP 73834 (Buffalo, $72,500 median) and poorest ZIP 73848 (Laverne, $57,619) are 26.6 miles apart — a 1.3× income gap across local geography.

Median home values vary 3.2× across this county — from $57,300 in 73851 (May) to $185,700 in 73855 (Rosston).

Density varies across the county — from 1 people/sq mi in 73855 (Rosston) to 3 in 73834 (Buffalo).

Educational attainment ranges from 19.8% bachelor's+ in 73851 (May) to 61.6% in 73855 (Rosston) — the breadth of educational profiles across the area.

Within Oklahoma, this is the #76 most populous of 78 counties and ranks #28 for median household income .

Weighted by population, the typical household earns about $64,769 across the county — reflecting what a typical resident sees, not a simple ZIP average.

29.9% of adults age 25+ hold a bachelor's degree or higher (741 of 2,475 reporting).

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

Stories about Harper 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
1,328
square miles
Avg density
2.6
people per sq mi
Population
3,463
across 4 ZIPs
Laverne
586.5 sq mi
1,555 residents
Buffalo
498.7 sq mi
1,544 residents
Rosston
184.0 sq mi
253 residents

Population decline

Harper County lost 12.7% of residents between 2014 and 2024. ZIPs that shed the largest share:

Laverne
-22.4%
2,004 → 1,555 residents
Buffalo
-13.3%
1,781 → 1,544 residents

All ZIP Codes in Harper County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
73848LaverneStandard1,555$57,619586.5-22.4%
73834BuffaloStandard1,544$72,500498.7-13.3%
73855RosstonStandard253$63,333184.0216.3%
73851MayStandard111$60,66258.39.9%

Adjacent & Nearby Counties