Illinois Route 63 (IL 63) was an east–west state highway in the Chicago metropolitan area.

Continuing northeast, it then briefly ran concurrently with IL 62 in Barrington Hills.

At this point, the route turned northeast along Midlothian Road.

[5] By 1934, US 14's eastern extension was established to travel along several state routes (including IL 63) in order to get to Chicago.

[7] By 1939, IL 63 was extended northeast roughly along present-day Illinois Route 22 (from North Barrington to Lake Zurich), Midlothian Road (from Lake Zurich to Mundelein), Illinois Route 176 (from Mundelein to Libertyville), and Illinois Route 21 (from Libertyville to Gurnee).