Alta is a small unincorporated community and census-designated place (CDP) in Placer County, California, United States, about 30 miles (48 km) 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.