Cinco Ranch is a census-designated place and master-planned community located in the extraterritorial jurisdiction of the city of Houston within Fort Bend and Harris counties in the U.S. state of Texas. The population was 18,274 at the 2010 census. It lies about 25 miles (40 km) west of the Harris County seat of Houston and 10 miles (16 km) north of the Fort Bend County seat of Richmond.