The Geography of Indiana refers to the U.S. State of Indiana. Indiana is in the north-central U.S. and borders on Lake Michigan. Surrounding states are Michigan to the north, Illinois to the west, Kentucky to the south, and Ohio to the east. The entire southern boundary is the Ohio River.

Indiana is bounded on the north by Lake Michigan and the state of Michigan; on the east by Ohio; on the south by Kentucky, with which it shares the Ohio River as a border; and on the west by Illinois. Indiana is one of the Great Lakes states.

The northern boundary of the states of Ohio, Indiana, and Illinois was originally defined to be a latitudinal line drawn through the southernmost tip of Lake Michigan. Since such a line did not provide Indiana with usable frontage on the lake, its northern border was shifted ten miles (16 km) north when it was granted statehood in 1816.

The 475 mile (764 km) long Wabash River bisects the state from northeast to southwest before flowing south, mostly along the Indiana-Illinois border. The river has given Indiana a few theme songs, such as On the Banks of the Wabash, The Wabash Cannonball and Back Home Again, In Indiana. The Wabash is the longest free-flowing river east of the Mississippi River, traversing 400 miles (640 km) from the Huntington dam to the Ohio River. The White River, a tributary of the Wabash, zigzags through central Indiana.

Indiana (ⁱ/ɪndiˈænə/) is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the midwestern and Great Lakes regions of North America. Indiana is the 38th largest by area and the 15th most populous of the 50 United States. Indiana is the least extensive state in the continental US west of the Appalachian Mountains. Its capital and largest city is Indianapolis, the second largest of any state capital and largest state capital east of the Mississippi River.

Before it became a territory, varying cultures of indigenous peoples and historic Native Americans inhabited Indiana for thousands of years. Angel Mounds State Historic Site, one of the best preserved ancient earthwork mound sites in the United States, can be found in Southwestern Indiana near Evansville. Residents of Indiana are known as Hoosiers. The etymology of the word is disputed, but the leading theory as advanced by the Indiana Historical Bureau and the Indiana Historical Society has "Hoosier" originating from the upland South region of the U.S. as a derogatory slang term for a rough countryman, a country bumpkin.