San Juan County area

Population and density of San Juan County

The Census Bureau estimates that 813 people lived in San Juan County on July 1, 2025. That ranks #3,195 of 3,222 county equivalents nationally and #63 of 64 in Colorado. Since the April 1, 2020 estimates base of 704, the population has grown by 109 (+15.5%), compared with +4.1% for Colorado as a whole.

With 387.5 square miles of land, that is 2.1 people per square mile (0.81 per km²), placing San Juan County #3,058 nationally for density and #56 in Colorado. The median county equivalent has 47 people per square mile; the Colorado median is 11. Put another way, there are about 305 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 San Juan County

1 incorporated place lies at least partly in San Juan County. Together they are home to 721 people (88.7%); the other 92 (11.3%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Silverton town, with 721 residents in the county.

Metropolitan area

San Juan 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

2 ZIP Code Tabulation Areas have land in San Juan County; 1 of them have most of their land inside the county, and the others mainly cover neighboring areas.

8130181433

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 San Juan County

San Juan County shares a land border with 5 county equivalents. Each of them has more land than San Juan County. The largest neighbor is La Plata County (1,689.7 mi²) and the smallest is Ouray County (540.7 mi²). Together with its neighbors, San Juan County forms a block of 6,089 mi² of land, of which it holds 6.4%.

How big is San Juan County compared with U.S. states?

San Juan County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.7 times as much. Colorado’s county land could hold about 267 areas the size of San Juan County.

Another way to picture it: the same land area would fill a square about 19.7 miles (31.7 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 San Juan County?

San Juan County has more land than 645 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 San Juan County at #2,638 nationally by total area, 61 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 0.2%, compared with a national county-equivalent median of 1.2% — 1 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 San Juan 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.