1. Sioux Falls Regional Airport 2. BNSF railway owns the most tracks in the state3. Black Hills National Forest, Buffalo Gap National Grassland, Fort Pierre National Grassland
The largest airport is in Sioux Falls.http://money.cnn.com/galleries/2008/fsb/��The largest railroad is BNSF Railway.http://www.en.wikipedia.org/wiki/South_d��Two national parks are Badlands and Wind Cave, and Bear Butte State Park.http://www.sdgfp.info/Parks
Well, I know that Mt Rushmore and The Black Hills are there.