Illinois State Route 4 is in Washington County for less than one mile. Only the westbound lane of IL St Rt 4 is. IL St Rt 4 does not pass through any town in Washington County IL St Rt 4 multi-plexes in Washington County Illinois State Route 13, near Tilton. IL St Rt 4 does not intersect any route in Washington County.
A Washington County mile marker.
NB IL St Rt 4/WB IL St Rt 13 at the Randolph/Washington County Line.
NB IL St Rt 4/WB IL St Rt 13 in its short passage through Washington County. The lane on the right, from the curve to the bridge is Washington County. The left lane from the bridge and around the curve is in St. Clair County.