Illinois State Route 91 runes east-west for aprox. one mile in the far southeastern portion of Henry County. IL St Rt 91 does not pass through any towns in Henry County. IL St Rt 91 is not multi-plexed in Henry County. IL St Rt 91 intersects the following highways in Henry County. U.S. Rt. 34, south of Kewanee. Illinois State Route 78, south of Kewanee.
A junction marker on WB U.S. Rt. 34/SB IL St Rt 78.