Area code 303 is one of the original area codes established in 1947 and originally served the entire state of Colorado. Today, it primarily covers the Denver metropolitan area, including Boulder, Aurora, and Lakewood. Over the years, 303 has been split (giving rise to 719 and 970) and overlaid with 720 and, more recently, 983. Despite these changes, 303 remains iconic and widely recognized as a symbol of the Mile High City. It is frequently referenced in local businesses, sports teams, and cultural events. With Denver’s rise as a tech and lifestyle hub, the 303 area code continues to reflect both history and growth in Colorado’s capital region.