The City of Aurora is a Home Rule Municipality in the State of Colorado, spanning Arapahoe and Adams counties, with the extreme southeastern portion of the city extending into Douglas County. Aurora is one of the principal cities of the Denver-Aurora-Broomfield, CO Metropolitan Statistical Area. Wikipedia

Great Sand Dunes National Park and Preserve is a United States National Park located in the San Luis Valley, in the easternmost parts of Alamosa County and Saguache County, Colorado, United States. Wikipedia