The State of Indiana is located in the midwestern region of the United States of America, south of Lake Michigan, which makes it one of the Great Lakes states. Northern Indiana has swell and swale topography, which means a change of hills and valles with wetland. Such a topography is ideal for a great biodiversity, but does not support karstification. Central Indiana with the state capital, Indianapolis, is characterized by gently rolling hills and sandstone ravines carved out by the retreating glaciers.
Karst and caves are concentrated to Southern Indiana, with over 2,600 known caves, including some of the longest in the United States. It is one of the largest limestone quarry regions in the USA, and there are also large coal mines.