It runs from U.S. Route 24 (US 24) just east of Camp Point to U.S. Route 67 just south of Oak Grove, just south of the Quad Cities area.

[1] Illinois 94 follows a complicated route north from Camp Point on its way to the Quad Cities area, making no fewer than eighteen 90-degree turns along the length of the route.

SBI Route 94 ran from Taylor Ridge, west of U.S. 67, to La Harpe, at Illinois 9.

There was also a spur to Alexis, northwest of Galesburg.

In 1955 it was extended further south to its current terminus, partially replacing Illinois Route 102.