Clifton is a census-designated place (CDP) and post office in and governed by Mesa County, Colorado, United States. It is part of the Grand Junction, CO Metropolitan Statistical Area. The Clifton post office has the ZIP Code 81520. As of the 2020 census, the population of the Clifton CDP was 20,413.

Mesa County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 155,703. The county seat and most populous municipality is Grand Junction. The county was named for the many large mesas in the area, including the Grand Mesa, which is the largest flat-topped mountain in the world.