ZIP Codes of Union County, NM

Population & People
Population & People
Total Population
4,188
Household Income
Household Income
Median Income
$63,281
Housing
Housing
Total Housing Units
2,153
Business & Economy
Business & Economy
Total Businesses
85
Employment
Employment
Employment Rate
41.05%
Education
Education
Bachelor's Degree+
18.87%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 8 ZIPs in this county.
Data Last Updated: July 1, 2026
ZIP Codes:8 ZIP Codes (8 Standard, 0 PO Box, 0 Unique) [See All]
Area Code:575
Timezone:Mountain (GMT -07:00)
Local Time:11:54:31 PM
Population:4,188 [See All]
FIPS:35059
Land Area:4,190 sq mi
Water Area:6 sq mi
Coordinates:36.4561, -103.5339
Quick Link:
https://www.zip-codes.com/county/nm-union.asp
Need Union data in your app? Look up ZIP, county, and city data with a single API call.
Try Free
Striking education divide
Bachelor's share spans 15.2% to 55.7% — a 41-point gap.

Standout ZIPs in this County


Most Populous
Clayton · 3,178 people
75.9% of county total
Highest Income
Folsom · $96,250 median
1.5× county average
Largest Land Area
Clayton · 1,286.9 sq mi
Spans the most ground
Fastest Growth
Clayton · -10.8% (10-yr)
3,564 → 3,178 residents
Most Educated
Clayton · 17.3% bachelor's+
411 of 2,370 adults 25+

Things worth knowing about Union County


4,188 residents live across 8 ZIPs covering 4,190 sq mi, served by 8 distinct USPS-recognized cities.

Population moved from 4,444 to 4,188 from 2014 to 2024 — a -5.8% change. 5 ZIPs gained residents, 3 lost.

The county's wealthiest ZIP 88419 (Folsom, $96,250 median) and poorest ZIP 88415 (Clayton, $44,952) are 31.7 miles apart — a 2.1× income gap across local geography.

Median home values vary 2.2× across this county — from $116,300 in 88422 (Gladstone) to $252,100 in 88419 (Folsom).

Density varies 27× across the county — from 0 people/sq mi in 88424 (Grenville) to 3 in 88414 (Capulin).

Educational attainment ranges from 15.2% bachelor's+ in 88424 (Grenville) to 55.7% in 88419 (Folsom) — the breadth of educational profiles across the area.

Within New Mexico, this is the #30 most populous of 34 counties and ranks #13 for median household income .

Weighted by population, the typical household earns about $50,606 across the county — reflecting what a typical resident sees, not a simple ZIP average.

18.9% of adults age 25+ hold a bachelor's degree or higher (582 of 3,085 reporting).

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

Stories about Union 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
4,190
square miles
Avg density
1.0
people per sq mi
Population
4,188
across 8 ZIPs
Clayton
1,286.9 sq mi
3,178 residents
Grenville
909.5 sq mi
89 residents
Des Moines
693.0 sq mi
536 residents

Single-ZIP anchor

One ZIP holds the majority of this county's population — a sign of a county built around a single city or town.

Clayton

Population decline

Union County lost 5.8% of residents between 2014 and 2024. ZIPs that shed the largest share:

Clayton
-10.8%
3,564 → 3,178 residents

All ZIP Codes in Union County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
88415ClaytonStandard3,178$44,9521,286.9-10.8%
88418Des MoinesStandard536$77,813693.061.9%
88414CapulinStandard13751.377.9%
88422GladstoneStandard117$61,346266.436.0%
88424GrenvilleStandard89909.548.3%
88419FolsomStandard61$96,250521.8-69.2%
88410AmistadStandard45$36,042327.480.0%
88436SedanStandard25134.2-75.7%

Adjacent & Nearby Counties