The Illinois Subdivision is a railroad line owned and operated by CSX Transportation in the U.S. states of Indiana and Illinois. The line runs from Washington, Indiana west to East St. Louis, Illinois[1] along a former Baltimore and Ohio Railroad line.
At its east end, the Illinois Subdivision becomes the Indiana Subdivision. At its west end in East St. Louis, near the west end of the St. Louis Line Subdivision, it meets the Terminal Railroad Association of St. Louis. Along the way, the line intersects the CE&D Subdivision at Vincennes, Indiana.
The line, built by the Ohio and Mississippi Railroad, was completed in 1857.[2] It passed to the Baltimore and Ohio Railroad and CSX via leases and mergers.