Interior is a town in Jackson County, South Dakota, United States.
Interior, South Dakota, is a small town in rural Jackson County. Interior is best known as the gateway to Badlands National Park, with various lodging options for visitors to the famed badlands region, which sprawls over 10,000 square miles of prairies and grasslands. Interior is just south of the park entrance.
Source:
https://en.wikipedia.org/wiki/Interior,_South_Dakota
http://traveltips.usatoday.com/lodging-interior-south-dakota-13164.html