Area code 605 covers the entire state of South Dakota and is one of the few single area codes still in use statewide. Established in 1947 as one of the original area codes, it serves cities such as Sioux Falls, Rapid City, Aberdeen, and Pierre. The state’s small population and geographic distribution have allowed 605 to remain unchanged without the need for splits or overlays. It is frequently used in statewide marketing and business names, serving as a recognizable badge of South Dakota identity. The code spans a diverse landscape of agriculture, tourism, and tribal nations. 605 is a proud symbol of the state’s unity and rural heritage.