County outline
Where Mono County is located
Area breakdown
Land accounts for 97.4% of Mono County’s measured area and water for 2.6%. Its combined area converts to 8,111.3 square kilometers or approximately 2,004,351 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 3,048.904 | 7,896.625 | 1,951,298.6 |
| Water | 82.894 | 214.694 | 53,052.2 |
| Total | 3,131.798 | 8,111.32 | 2,004,350.7 |
How Mono County compares
By original Census land area, Mono County ranks #19 of 58 in California and #169 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 1.985 times the California county-equivalent median of 1,535.7 square miles. It accounts for 2% of the combined county land area in the state.
See the complete California ranking · What counts as a county equivalent?
Population and density of Mono County
The Census Bureau estimates that 12,505 people lived in Mono County on July 1, 2025. That ranks #2,321 of 3,222 county equivalents nationally and #55 of 58 in California. Since the April 1, 2020 estimates base of 13,199, the population has declined by 694 (−5.3%), compared with −0.5% for California as a whole.
With 3,048.9 square miles of land, that is 4.1 people per square mile (1.6 per km²), placing Mono County #2,897 nationally for density and #54 in California. The median county equivalent has 47 people per square mile; the California median is 112. Put another way, there are about 156 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 13,222 | 13,258 | 12,982 | 13,082 | 12,692 | 12,505 |
| Change | — | +36 | −276 | +100 | −390 | −187 |
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 Mono County
1 incorporated place lies at least partly in Mono County. Together they are home to 6,867 people (54.9%); the other 5,638 (45.1%) live outside any incorporated place, in unincorporated communities and rural areas.
The largest is Mammoth Lakes town, with 6,867 residents in the county.
Metropolitan area
Mono 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
9 ZIP Code Tabulation Areas have land in Mono County; 8 of them have most of their land inside the county, and the others mainly cover neighboring areas.
890109351293514935179352993541935469610796133
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 Mono County
Mono County shares a land border with 9 county equivalents, including 4 in Nevada. It has more land than 5 of them. The largest neighbor is Inyo County (10,197.3 mi²) and the smallest is Douglas County (710.5 mi²). Together with its neighbors, Mono County forms a block of 34,347.5 mi² of land, of which it holds 8.9%.
| Bordering county equivalent | Land mi² | Size vs. Mono | Compare |
|---|---|---|---|
| Inyo County | 10,197.3 | 3.3× larger | Compare |
| Fresno County | 5,958.6 | 2× larger | Compare |
| Mineral CountyNevada | 3,751.3 | 1.2× larger | Compare |
| Esmeralda CountyNevada | 3,581.9 | 1.2× larger | Compare |
| Tuolumne County | 2,220.9 | 1.4× smaller | Compare |
| Madera County | 2,136.7 | 1.4× smaller | Compare |
| Lyon CountyNevada | 2,003.1 | 1.5× smaller | Compare |
| Alpine County | 738.3 | 4.1× smaller | Compare |
| Douglas CountyNevada | 710.5 | 4.3× smaller | Compare |
How big is Mono County compared with U.S. states?
Mono County has more land than 2 of the 50 states. It is about 1.6 times the land area of Delaware (1,948.6 mi²), while Connecticut, the next larger state, has 1.6 times as much land (4,842.5 mi²). California’s county land could hold about 51 areas the size of Mono County.
Another way to picture it: the same land area would fill a square about 55.2 miles (88.9 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 Mono County?
Mono County has more land than 3,053 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 Mono County at #179 nationally by total area, 10 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 2.6%, compared with a national county-equivalent median of 1.2% — 1.5 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 Mono County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #168 | Baker County, Oregon | 3,068 | Compare |
| #169 | Mono County, California | 3,048.9 | This county |
| #170 | Guadalupe County, New Mexico | 3,029.8 | 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 37.909925, -118.879072. 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: 7,896,625,291 m²; AWATER: 214,695,143 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 Mono County?
Mono County, California has 3,048.9 square miles (7,896.6 km²) of land and 82.9 square miles of water, for a total area of 3,131.8 square miles. It ranks #169 of 3,222 U.S. county equivalents by land area.
Is Mono County the largest county in California?
No. Mono County ranks #19 of 58 in California by land area. The largest is San Bernardino County, with 20,068.4 square miles of land.
What counties border Mono County?
Mono County shares a land border with Tuolumne County, Mineral County, Nevada, Inyo County, Esmeralda County, Nevada, Alpine County, Madera County, Douglas County, Nevada, Fresno County, and Lyon County, Nevada.
What is the population of Mono County?
The Census Bureau estimates Mono County had 12,505 residents on July 1, 2025, ranking #2,321 of 3,222 county equivalents. That is 4.1 people per square mile of land.
What is the county seat of Mono County?
The county seat of Mono County is Bridgeport.
Is Mono County part of a metropolitan area?
No. Mono County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.
How many ZIP codes are in Mono County?
9 ZIP Code Tabulation Areas have land in Mono 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 Mono County compare with U.S. states?
It has more land than 2 of the 50 states, including Delaware (1,948.6 square miles of land).
How many acres of land are in Mono County?
The land measurement converts to approximately 1,951,299 acres. Including water, total area is approximately 2,004,351 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.