Alta (Spanish for "Upper") is a small unincorporated community and census-designated place (CDP) in Placer County, California, United States, about northeast of Auburn. The village is located off Interstate 80 and along the historical First transcontinental railroad. The ZIP code is 95701 and the area code 530. One of the few buildings other than private residences is the Alta-Dutch Flat Grammar School serving kindergarten through eighth grade students. The high school that serves Alta is named Colfax High School. Colfax High School is 11 miles southwest in the incorporated town of Colfax. The population of Alta was 615 at the 2020 census. A historical California place once named Alta was located in San Diego County near the present-day La Mesa–El Cajon boundary. This historical place was along the San Diego and Arizona Eastern Railway, now the San Diego Trolley Orange Line, at its Murray Drive undercrossing in La Mesa. The community was named after the Spanish word meaning "upper" or "high". Geography According to the United States Census Bureau, the CDP covers an area of 2.4 square miles (6.2 km2), 99.72% of it land, and 0.28% of it water. Climate Alta has a hot-summer Mediterranean climate (Köppen climate classification Csa) that is characterized by cool, wet winters and hot, dry summers (Köppen climate classification Csa). Demographics The 2010 United States Census reported that Alta had a population of 610. The population density was . The racial makeup of Alta was 592 (97.0%) White, 1 (0.2%) African American, 3 (0.5%) Native American, 5 (0.8%) Asian, 1 (0.2%) Pacific Islander, 2 (0.3%) from other races, and 6 (1.0%) from two or more races. Hispanic or Latino of any race were 23 persons (3.8%). The Census reported that 594 people (97.4% of the population) lived in households, 16 (2.6%) lived in non-institutionalized group quarters, and 0 (0%) were institutionalized. There were 242 households, out of which 70 (28.9%) had children under the age of 18 living in them, 141 (58.3%) were opposite-sex married couples living together, 17 (7.0%) had a female householder with no husband present, 14 (5.8%) had a male householder with no wife present. There were 18 (7.4%) unmarried opposite-sex partnerships, and 1 (0.4%) same-sex married couples or partnerships. 56 households (23.1%) were made up of individuals, and 19 (7.9%) had someone living alone who was 65 years of age or older. The average household size was 2.45. There were 172