County outline
Where San Juan County is located
Area breakdown
Land accounts for 98.6% of San Juan County’s measured area and water for 1.4%. Its combined area converts to 20,548.5 square kilometers or approximately 5,077,638 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 7,823.687 | 20,263.256 | 5,007,159.7 |
| Water | 110.122 | 285.215 | 70,478.1 |
| Total | 7,933.809 | 20,548.471 | 5,077,637.8 |
How San Juan County compares
By original Census land area, San Juan County ranks #1 of 29 in Utah and #38 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 3.223 times the Utah county-equivalent median of 2,427.6 square miles. It accounts for 9.5% of the combined county land area in the state.
See the complete Utah ranking · What counts as a county equivalent?
Population and density of San Juan County
The Census Bureau estimates that 14,542 people lived in San Juan County on July 1, 2025. That ranks #2,186 of 3,222 county equivalents nationally and #17 of 29 in Utah. Since the April 1, 2020 estimates base of 14,512, the population has grown by 30 (+0.2%), compared with +8.2% for Utah as a whole.
With 7,823.7 square miles of land, that is 1.9 people per square mile (0.72 per km²), placing San Juan County #3,077 nationally for density and #26 in Utah. The median county equivalent has 47 people per square mile; the Utah median is 11. Put another way, there are about 344 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 14,521 | 14,489 | 14,383 | 14,324 | 14,499 | 14,542 |
| Change | — | −32 | −106 | −59 | +175 | +43 |
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
3 incorporated places lie at least partly in San Juan County. Together they are home to 5,188 people (35.7%); the other 9,354 (64.3%) live outside any incorporated place, in unincorporated communities and rural areas.
The largest is Blanding city, with 3,199 residents in the county. The county seat, Monticello city, has 1,737 residents. By land, Bluff town is the largest at 36.6 mi².
| Incorporated place | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Blanding city | 3,199 | −5.5% | 13.2 |
| Monticello cityCounty seat | 1,737 | −5% | 3.351 |
| Bluff town | 252 | +3.3% | 36.6 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside San Juan County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.
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
12 ZIP Code Tabulation Areas have land in San Juan County; 8 of them have most of their land inside the county, and the others mainly cover neighboring areas.
813248451184512845308453184532845338453484535845368604486514
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 11 county equivalents, including 7 in Arizona and Colorado. It has more land than 8 of them. The largest neighbor is Coconino County (18,616.4 mi²) and the smallest is Dolores County (1,067.2 mi²). Together with its neighbors, San Juan County forms a block of 69,519.8 mi² of land, of which it holds 11.3%.
| Bordering county equivalent | Land mi² | Size vs. San Juan | Compare |
|---|---|---|---|
| Coconino CountyArizona | 18,616.4 | 2.4× larger | Compare |
| Apache CountyArizona | 11,198.4 | 1.4× larger | Compare |
| Navajo CountyArizona | 9,949.5 | 1.3× larger | Compare |
| Garfield County | 5,179.6 | 1.5× smaller | Compare |
| Kane County | 3,994.1 | 2× smaller | Compare |
| Grand County | 3,672.9 | 2.1× smaller | Compare |
| Wayne County | 2,461.1 | 3.2× smaller | Compare |
| Montrose CountyColorado | 2,240.9 | 3.5× smaller | Compare |
| Montezuma CountyColorado | 2,029.3 | 3.9× smaller | Compare |
| San Miguel CountyColorado | 1,286.7 | 6.1× smaller | Compare |
| Dolores CountyColorado | 1,067.2 | 7.3× smaller | Compare |
How big is San Juan County compared with U.S. states?
San Juan County has more land than 6 of the 50 states. It is about 1 times the land area of Massachusetts (7,801 mi²), while New Hampshire, the next larger state, has 1.1 times as much land (8,954 mi²). Utah’s county land could hold about 11 areas the size of San Juan County.
Another way to picture it: the same land area would fill a square about 88.5 miles (142.3 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 3,184 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 #44 nationally by total area, 6 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 1.4%, 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 San Juan County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #37 | Clark County, Nevada | 7,891.7 | Compare |
| #38 | San Juan County, Utah | 7,823.7 | This county |
| #39 | Owyhee County, Idaho | 7,668.2 | Compare |
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.
Representative coordinates
The Census internal point is 37.602633, -109.791574. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.
Source and precision
U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 20,263,255,791 m²; AWATER: 285,213,894 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.
Common questions
How big is San Juan County?
San Juan County, Utah has 7,823.7 square miles (20,263.3 km²) of land and 110.1 square miles of water, for a total area of 7,933.8 square miles. It ranks #38 of 3,222 U.S. county equivalents by land area.
Is San Juan County the largest county in Utah?
Yes. San Juan County has the most land of the 29 county equivalents in Utah.
What counties border San Juan County?
San Juan County shares a land border with Kane County, Garfield County, Apache County, Arizona, Grand County, Navajo County, Arizona, Coconino County, Arizona, Montezuma County, Colorado, Dolores County, Colorado, Wayne County, Montrose County, Colorado, and San Miguel County, Colorado.
What is the population of San Juan County?
The Census Bureau estimates San Juan County had 14,542 residents on July 1, 2025, ranking #2,186 of 3,222 county equivalents. That is 1.9 people per square mile of land.
What is the county seat of San Juan County?
The county seat of San Juan County is Monticello.
What cities and towns are in San Juan County?
San Juan County has 3 incorporated places. The most populous are Blanding city, Monticello city, and Bluff town; 9,354 residents live outside any incorporated place.
Is San Juan County part of a metropolitan area?
No. San Juan County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.
How many ZIP codes are in San Juan County?
12 ZIP Code Tabulation Areas have land in San Juan County, and 8 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does San Juan County compare with U.S. states?
It has more land than 6 of the 50 states, including Massachusetts (7,801 square miles of land).
How many acres of land are in San Juan County?
The land measurement converts to approximately 5,007,160 acres. Including water, total area is approximately 5,077,638 acres. One square mile equals 640 acres.
Why might another source show a different area?
Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.
Can this establish a property boundary?
No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.