Indiana Borders: States, Map & Complete Guide

Michigan and Indiana are separated by a border located on Indiana's northern edge. The boundary runs roughly east-west from Ohio in the east to Illinois and Lake Michigan in the west.

The Indiana-Michigan border extends for about 120 miles on land. The border follows a relatively straight line across northern Indiana. Indiana counties along this border include Steuben, LaGrange, Elkhart, St. Joseph, LaPorte, and Porter. On the Michigan side, Branch, St. Joseph, Cass, and Berrien counties sit along the border. South Bend, Indiana is located near this border.

Ohio and Indiana are separated by a border located on Indiana's eastern edge. The boundary runs roughly north-south from Michigan in the north to Kentucky in the south, following a relatively straight survey line.

The Indiana-Ohio border extends for about 175 miles. The border follows a mostly straight north-south line. Indiana counties along this border include Steuben, DeKalb, Allen, Wells, Adams, Jay, Randolph, Wayne, Union, Fayette, Franklin, Dearborn, and Ohio. Major cities near this border include Fort Wayne, Indiana and Cincinnati, Ohio (just across from southeastern Indiana).

Kentucky and Indiana are separated entirely by the Ohio River along Indiana's southern edge. This makes the Indiana-Kentucky border unique—it's formed completely by a single river for the full length of the state.

The Indiana-Kentucky border extends for about 345 miles along the Ohio River from Illinois in the west to Ohio in the east. The river creates a natural boundary that follows the northern bank of the Ohio River. Indiana counties along this border include Posey, Vanderburgh, Warrick, Spencer, Perry, Crawford, Harrison, Floyd, Clark, Scott, Jefferson, Switzerland, and Ohio. Major cities on this border include Evansville and New Albany in Indiana, and Louisville in Kentucky.

Illinois and Indiana are separated by a border located on Indiana's western edge. The Wabash River forms the southern portion of this boundary, creating a natural water border.

The Indiana-Illinois border extends for about 350 miles total from Lake Michigan in the north to Kentucky in the south. The Wabash River creates the border for about 200 miles in the southern section, while a land border marks the northern section. Indiana counties along this border include Lake, Porter, LaPorte, Newton, Jasper, White, Benton, Warren, Tippecanoe, Fountain, Vermillion, Parke, Vigo, Sullivan, Knox, and Posey.

Lake Michigan forms Indiana's northwestern boundary, providing the state's only water access to the Great Lakes. The lake shore stretches from the Michigan border in the east to the Illinois border in the west.

Indiana's Lake Michigan coastline is about 45 miles long, the shortest of any state bordering the Great Lakes. Only two counties in Indiana touch Lake Michigan: Lake County and Porter County. The Indiana Dunes National Park sits along this shoreline, and cities like Gary, Hammond, and Michigan City are located on the lake. The Port of Indiana-Burns Harbor provides important shipping access to the Great Lakes.