[1] Illinois 170 is a rural, two-lane surface road for its entire length.

The road crosses Illinois River via a four-span truss bridge.

[3] As of May 5, 2006, the Illinois Department of Transportation is looking to replace the 74-year-old bridge.

SBI Route 160 originally ran from Red Bud to Sparta; this became Illinois Route 154 in 1937.

In 1946, it replaced Illinois Route 186 (previously Illinois Route 70A) from Seneca south to Illinois Route 17 near Budd.