Colorado’s grape growing regions contain the highest elevation vineyards in the United States, with most viticulture in the state practiced between 4,000 and 7,000 feet above sea level. The largest and most revered rodeo in the world takes place in Colorado. The largest flat-top mountain in the world is located in Colorado. Countryaah.com: Offers a full list of nationwide and statewide holidays in Colorado starting from January 1st – New Year’s Day. Also covers the most recent three years of public holidays within the state of Colorado.