ZIP Codes of Slope County, ND

Population & People
Population & People
Total Population
273
Household Income
Household Income
Median Income
$69,532
Housing
Housing
Total Housing Units
193
Business & Economy
Business & Economy
Total Businesses
8
Employment
Employment
Employment Rate
51.52%
Education
Education
Bachelor's Degree+
38.86%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 2 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:2 ZIP Codes (2 Standard, 0 PO Box, 0 Unique) [See All]
Area Code:701
Timezone:Mountain (GMT -07:00)
Local Time:2:13:03 PM
Population:273 [See All]
FIPS:38087
Land Area:504 sq mi
Water Area:2 sq mi
Coordinates:46.4060, -103.6281
Quick Link:
https://www.zip-codes.com/county/nd-slope.asp
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Notable population decline
Lost 21.3% of residents since 2014.
Among America's 25 oldest counties
Median age 65.2 — #2 nationwide.
North Dakota's longest commutes
33-minute average travel time to work.
Among North Dakota's 5 most-educated counties
38.9% with bachelor's+ (#3 statewide).

Standout ZIPs in this County


Most Populous
Amidon · 154 people
56.4% of county total
Highest Income
Amidon · $76,875 median
1.1× county average
Largest Land Area
Amidon · 285.8 sq mi
Spans the most ground
Fastest Growth
— growth not calculable
Most Educated
— no education data

Things worth knowing about Slope County


273 residents live across 2 ZIPs covering 504 sq mi, served by 2 distinct USPS-recognized cities.

Population moved from 347 to 273 from 2014 to 2024 — a -21.3% change. 0 ZIPs gained residents, 2 lost.

The county's wealthiest ZIP 58620 (Amidon, $76,875 median) and poorest ZIP 58643 (Marmarth, $62,188) are 31.5 miles apart — a 1.2× income gap across local geography.

Density varies across the county — from 1 people/sq mi in 58620 (Amidon) to 1 in 58643 (Marmarth).

Educational attainment ranges from 25.3% bachelor's+ in 58643 (Marmarth) to 50.0% in 58620 (Amidon) — the breadth of educational profiles across the area.

Within North Dakota, this is the #63 most populous of 64 counties and ranks #43 for median household income .

Weighted by population, the typical household earns about $70,473 across the county — reflecting what a typical resident sees, not a simple ZIP average.

38.9% of adults age 25+ hold a bachelor's degree or higher (82 of 211 reporting).

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

Stories about Slope 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
504
square miles
Avg density
0.5
people per sq mi
Population
273
across 2 ZIPs
Amidon
285.8 sq mi
154 residents
Marmarth
218.6 sq mi
119 residents

Population decline

Slope County lost 21.3% of residents between 2014 and 2024.

All ZIP Codes in Slope County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
58620AmidonStandard154$76,875285.8-12.0%
58643MarmarthStandard119$62,188218.6-30.8%

Adjacent & Nearby Counties