South Dakota (South Dakota - SD) is located in the Midwest region of the United States. The capital city of the state is Pierre. South Dakota is a sparsely populated state with a land area of 199,905 square kilometers and a population of less than 1 million (780,000). There are many rivers in the state. The eastern part of South Dakota is prairie, which is an agricultural area, and the western part is the high plains. Agriculture and services are the state's most important industries. The area code of South Dakota is 605, the zip code of the main city Sioux Falls is 57193, and the zip code of Rapid City is 57701. More zip codes can be searched on this website.