The only incorporated city in the county is Mammoth Lakes, which is located at the foot of Mammoth Mountain. Other locations, such as June Lake, are also famous as skiing and fishing resorts. Located in the middle of the county is Mono Lake, a vital habitat for millions of migratory and nesting birds. The lake is located in a wild natural setting, with pinnacles of tufa arising out of the salty and alkaline lake.
Also located in Mono County is Bodie, the official state gold rush ghost town, which is now a California State Historic Park.
As of the census of 2000, there were 12,853 people, 5,137 households, and 3,143 families residing in the county. The population density was 4 inhabitants per square mile (1.5/km²). There were 11,757 housing units at an average density of 4/sq mi (1.5/km²). The racial makeup of the county was 84.17% White, 0.47% Black or African American, 2.40% Native American, 1.11% Asian, 0.09% Pacific Islander, 9.51% from other races, and 2.25% from two or more races. 17.69% of the population were Hispanic or Latino of any race. 13.4% were of German, 12.6% Irish and 11.4% English ancestry according to Census 2000. 84.0% spoke English and 15.1% Spanish as their first language.
There were 5,137 households out of which 28.7% had children under the age of 18 living with them, 50.6% were married couples living together, 6.5% had a female householder with no husband present, and 38.8% were non-families. 26.6% of all households were made up of individuals and 4.3% had someone living alone who was 65 years of age or older. The average household size was 2.43 and the average family size was 2.98.
In the county the population was spread out with 23.0% under the age of 18, 10.3% from 18 to 24, 33.4% from 25 to 44, 25.6% from 45 to 64, and 7.6% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 121.8 males. For every 100 females age 18 and over, there were 126.8 males.
The median income for a household in the county was $44,992, and the median income for a family was $50,487. Males had a median income of $32,600 versus $26,227 for females. The per capita income for the county was $23,422. About 6.30% of families and 11.50% of the population were below the poverty line, including 12.20% of those under age 18 and 1.90% of those age 65 or over.
Eastern Sierra Transit Authority operates intercity bus service along U.S. 395, as well as local services in Mammoth Lakes. Service extends south to Ridgecrest (Kern County) and north to Reno, Nevada.
Yosemite Area Regional Transit System (YARTS) also runs along U.S. 395 from Mammoth Lakes to Lee Vining before entering Yosemite National Park.
General aviation airports in Mono County include Bryant Field near Bridgeport, Mammoth Yosemite Airport and Lee Vining Airport. In December 2008, Mammoth Yosemite Airport began commercial air service to Los Angeles International Airport on a seasonal (December to April) basis; the service is provided by Horizon Air, and is subsidized by Mammoth Mountain Ski Resort.