Illinois Route 140

Route 140 begins at a junction with Route 143 in Alton. The route heads northeast through Alton to a junction with Illinois Route 3 and Illinois Route 111. From this junction, Route 140 heads east concurrently with Route 111. The highways run along the northern border of East Alton before entering Bethalto, where they meet Illinois Route 255. Shortly past the junction, Route 111 turns south, while Route 140 continues east, passing to the north of St. Louis Regional Airport. The highway runs through a rural area of Madison County, where it passes through the community of Meadowbrook and then intersects Illinois Route 159. As of 2026, the section traveling through Meadowbrook is designated the Cpl. Tommy N. Miller Memorial Highway^[3], following legislation passed by the Illinois General Assembly and sponsored by State Representative Amy Elik.^[4] The road then enters the village of Hamel, where it intersects Illinois Route 157 and Interstate 55. Past Hamel, the route crosses Illinois Route 4 before passing through Alhambra. The highway then intersects Illinois Route 160 before entering Bond County.^[5][6]

In Bond County, the route passes through farmland and runs south of Old Ripley. Past Old Ripley, the highway meets Illinois Route 127; the two highways overlap until Route 127 turns south at the western edge of Greenville. Route 140 continues east through northern Greenville, passing Greenville Regional Hospital. After leaving Greenville, the route heads east until turning north at an intersection north of Smithboro. The highway then heads east-northeast toward Mulberry Grove, parallel to and north of U.S. Route 40. In Mulberry Grove, the route enters along Wall Street before turning north along Maple Street. The highway then turns east along Main Street before leaving the village and entering Fayette County.^[7] The highway terminates east of Mulberry Grove at a junction with US 40.^[6][8]

• List of state routes in Illinois