ZIP Codes of Sierra County, NM

Population & People
Population & People
Total Population
11,500
Household Income
Household Income
Median Income
$48,161
Housing
Housing
Total Housing Units
8,200
Business & Economy
Business & Economy
Total Businesses
219
Employment
Employment
Employment Rate
35.87%
Education
Education
Bachelor's Degree+
17.02%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 10 ZIPs in this county.
Data Last Updated: July 1, 2026
ZIP Codes:10 ZIP Codes (8 Standard, 1 PO Box, 1 Unique) [See All]
Area Code:575
Timezone:Mountain (GMT -07:00)
Local Time:11:54:31 PM
Population:11,500 [See All]
FIPS:35051
Land Area:3,834 sq mi
Water Area:56 sq mi
Coordinates:33.0936, -107.3729
Quick Link:
https://www.zip-codes.com/county/nm-sierra.asp
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Wide geographic spread
ZIPs range from 1670.6 sq mi down to 8.42 — a 199× sprawl ratio.
Among New Mexico's 5 oldest counties
Median age 54.5.

Standout ZIPs in this County


Most Populous
Truth Or Consequences · 6,378 people
55.5% of county total
Highest Income
Hillsboro · $75,137 median
1.6× county average
Largest Land Area
Truth Or Consequences · 1,670.6 sq mi
Spans the most ground
Fastest Growth
Elephant Butte · 16.9% (10-yr)
1,791 → 2,094 residents
Most Educated
Truth Or Consequences · 18.3% bachelor's+
852 of 4,663 adults 25+

Things worth knowing about Sierra County


11,500 residents live across 10 ZIPs covering 3,834 sq mi, served by 10 distinct USPS-recognized cities.

Population moved from 11,764 to 11,500 from 2014 to 2024 — a -2.2% change. 5 ZIPs gained residents, 3 lost (and 1 held flat).

The county's wealthiest ZIP 88042 (Hillsboro, $75,137 median) and poorest ZIP 87901 (Truth Or Consequences, $34,242) are 43.5 miles apart — a 2.2× income gap across local geography.

Median home values vary 1.7× across this county — from $114,800 in 87942 (Williamsburg) to $197,700 in 87935 (Elephant Butte).

Density varies 1380× across the county — from 0 people/sq mi in 88042 (Hillsboro) to 363 in 87935 (Elephant Butte).

Educational attainment ranges from 6.8% bachelor's+ in 88042 (Hillsboro) to 28.6% in 87939 (Monticello) — the breadth of educational profiles across the area.

Within New Mexico, this is the #26 most populous of 34 counties and ranks #28 for median household income .

Hosts 1 single-entity Unique ZIP: 87654Spaceport America .

Weighted by population, the typical household earns about $39,474 across the county — reflecting what a typical resident sees, not a simple ZIP average.

17.0% of adults age 25+ hold a bachelor's degree or higher (1,576 of 9,259 reporting).

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

Stories about Sierra 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
3,834
square miles
Avg density
3.0
people per sq mi
Population
11,500
across 10 ZIPs
Truth Or Consequences
1,670.6 sq mi
6,378 residents
Hillsboro
779.4 sq mi
205 residents
Winston
687.4 sq mi
191 residents

All ZIP Codes in Sierra County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
87901Truth Or ConsequencesStandard6,378$34,2421,670.6-5.9%
87935Elephant ButtePO Box2,094$51,0335.816.9%
87942WilliamsburgStandard1,005$42,308153.818.7%
87930ArreyStandard718$38,08517.4-34.5%
87931CaballoStandard703132.910.7%
87939MonticelloStandard206378.69.6%
88042HillsboroStandard205$75,137779.4-14.9%
87943WinstonStandard191687.42.1%
87933DerryStandard08.4
87654Spaceport CityUnique0.0

Adjacent & Nearby Counties