Illinois Route 14 is a major east–west highway in southern Illinois. It runs from U.S. Route 51 south of Du Quoin to the New Harmony Toll Bridge over the Wabash River to State Road 66 at the Indiana state line. This is a distance of 76.24 miles (122.70 km).

Illinois 14 runs mostly east–west from Du Quoin to New Harmony, Indiana via State Road 66.

The eastern terminus of Illinois 14 is the New Harmony Toll Bridge to New Harmony, Indiana, which bridges the states of Illinois and Indiana. The bridge is a four-span truss bridge built in 1931. It was originally built as a toll bridge, but has been closed to automobile traffic since May 21, 2012.

Illinois Route 14 followed the present-day routing of Illinois 14, from Du Quoin to Carmi. In 1937 it was extended east to its current terminus across from New Harmony, Indiana, replacing Illinois Route 139 in the process.

From 1947 to 1974, U.S. Route 460 replaced Illinois 14 between McLeansboro and the Indiana state line; after 1974, the extended routing of 1937 was restored.