Sierra County area

Population and density of Sierra County

The Census Bureau estimates that 11,395 people lived in Sierra County on July 1, 2025. That ranks #2,397 of 3,222 county equivalents nationally and #25 of 33 in New Mexico. Since the April 1, 2020 estimates base of 11,572, the population has declined by 177 (−1.5%), compared with +0.4% for New Mexico as a whole.

With 4,181.2 square miles of land, that is 2.7 people per square mile (1.1 per km²), placing Sierra County #3,005 nationally for density and #25 in New Mexico. The median county equivalent has 47 people per square mile; the New Mexico median is 6.9. Put another way, there are about 235 acres of land per resident.

U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.

Cities and towns in Sierra County

3 incorporated places lie at least partly in Sierra County. Together they are home to 7,863 people (69%); the other 3,532 (31%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Truth or Consequences city, with 5,949 residents in the county. Among places with at least 1,000 residents in 2020, Elephant Butte city grew fastest since then (+0.1%).

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Sierra County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

Sierra County is not part of any metropolitan or micropolitan statistical area in the Office of Management and Budget’s July 2023 delineation; 1,306 other county equivalents are also outside one. These areas are built around an urban core of at least 10,000 people plus the counties tied to it by commuting, so counties outside them are generally rural.

ZIP codes

10 ZIP Code Tabulation Areas have land in Sierra County; 8 of them have most of their land inside the county, and the others mainly cover neighboring areas.

87901879308793187933879358793687939879428794388042

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Sierra County

Sierra County shares a land border with 7 county equivalents. It has more land than 3 of them. The largest neighbor is Catron County (6,924.2 mi²) and the smallest is Luna County (2,965.2 mi²). Together with its neighbors, Sierra County forms a block of 39,930 mi² of land, of which it holds 10.5%.

How big is Sierra County compared with U.S. states?

Sierra County has more land than 2 of the 50 states. It is about 2.1 times the land area of Delaware (1,948.6 mi²), while Connecticut, the next larger state, has 1.2 times as much land (4,842.5 mi²). New Mexico’s county land could hold about 29 areas the size of Sierra County.

Another way to picture it: the same land area would fill a square about 64.7 miles (104.1 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.

State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.

What stands out about Sierra County?

Sierra County has more land than 3,110 of the other 3,221 county equivalents in the dataset.

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Sierra County at #120 nationally by total area, 8 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.

Its water share is 1.3%, compared with a national county-equivalent median of 1.2% — 0.2 percentage points higher. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Sierra County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.