Rio Arriba County area

Population and density of Rio Arriba County

The Census Bureau estimates that 39,832 people lived in Rio Arriba County on July 1, 2025. That ranks #1,215 of 3,222 county equivalents nationally and #13 of 33 in New Mexico. Since the April 1, 2020 estimates base of 40,349, the population has declined by 517 (−1.3%), compared with +0.4% for New Mexico as a whole.

With 5,860.9 square miles of land, that is 6.8 people per square mile (2.6 per km²), placing Rio Arriba County #2,773 nationally for density and #18 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 94 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 Rio Arriba County

2 incorporated places lie at least partly in Rio Arriba County. Together they are home to 7,971 people (20%); the other 31,861 (80%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Española city, with 7,058 residents in the county (the city extends into 1 other county).

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

Metropolitan area

Rio Arriba County is a central county of the Española, NM Micropolitan Statistical Area. Rio Arriba County is the area’s only county equivalent, so the micro area has the same 5,860.9 square miles of land. By combined land it ranks #16 of 542 micropolitan areas, and #323 by population. It belongs to the Albuquerque-Santa Fe-Los Alamos, NM Combined Statistical Area.

ZIP codes

37 ZIP Code Tabulation Areas have land in Rio Arriba County; 30 of them have most of their land inside the county, and the others mainly cover neighboring areas.

81120870128701387017870188702987037870468706487412874198751087511875158751687518875208752187522875238752787528875308753187532875378753987548875498755187554875668757587577875788758187582

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 Rio Arriba County

Rio Arriba County shares a land border with 8 county equivalents, including 2 in Colorado. It has more land than every one of them. The largest neighbor is San Juan County (5,517.2 mi²) and the smallest is Los Alamos County (109.1 mi²). Together with its neighbors, Rio Arriba County forms a block of 23,873.9 mi² of land, of which it holds 24.5%.

How big is Rio Arriba County compared with U.S. states?

Rio Arriba County has more land than 3 of the 50 states. It is about 1.2 times the land area of Connecticut (4,842.5 mi²), while Hawaii, the next larger state, has 1.1 times as much land (6,422.6 mi²). New Mexico’s county land could hold about 21 areas the size of Rio Arriba County.

Another way to picture it: the same land area would fill a square about 76.6 miles (123.2 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 Rio Arriba County?

Rio Arriba County has more land than 3,159 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 Rio Arriba County at #68 nationally by total area, 5 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 0.6%, compared with a national county-equivalent median of 1.2% — 0.6 percentage points lower. 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 Rio Arriba 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.