It heads north through farmland into Towanda Township, passing through the community of Merna.

The route turns east after leaving Merna and enters Blue Mound Township.

The route heads northeast before turning east along the northern border of Colfax.

[3] Illinois 165 is a rural undivided two-lane road for its entire length.

[5] It was first marked on the 1929 highway map; at this point, the route between Cooksville and Colfax had not been paved.