Transportation
South Dakota has a total of 83,609 miles (134,556 km) of highways, roads, and streets, along with 679 miles (1,093 km) of interstate highways. Two major interstates pass through South Dakota: Interstate 90, which runs east and west; and Interstate 29, running north and south in the eastern portion of the state. Also located in the state are the shorter interstates 190 and 229. Several major U.S. highways pass through the state. U.S. routes 12, 14, 16, 18, and 212 travel east and west, while U.S. routes 81, 83, 85 and 281 run north and south. Railroads have played an important role in South Dakota transportation since the mid nineteenth century. Some 4,420 miles (7,113 km) of railroad track were built in South Dakota during the late nineteenth and early twentieth centuries, but only 1,839 miles (2,959 km) of railroad are currently operational. South Dakota's largest commercial airports are located at Sioux Falls and Rapid City.
Read more about this topic: Geography Of South Dakota, Human Geography