Sage is a census-designated place in Riverside County, California, United States. It has a population of 3,370 according to the 2020 census. It i…Sage is a census-designated place in Riverside County, California, United States. It has a population of 3,370 according to the 2020 census. It is a rural community with a history of farming, ranching, and bee keeping dating back to 1893. Sage is known for its views, hiking, multi-habitat species preserves, and close proximity to the Temecula Valley Wine Country. Its elevation is 2,313 feet.