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.[4] The old bridge was imploded on November 18, 2010.
History
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.[5][6][7] In 1995 Illinois 170 was extended further south to Illinois 23.[2]
^Illinois Secretary of State; Rand McNally (1936). Road Map Illinois (Map). [c. 1:950,000 and c. 1:1,110,000]. Springfield: Illinois Secretary of State – via Illinois Digital Archives.
^Illinois Secretary of State; Rand McNally (1939). Illinois Road Map (Map) (1939–1940 ed.). c. 1:918,720. Springfield: Illinois Secretary of State – via Illinois Digital Archives.
^Illinois Secretary of State; Rand McNally (1946). Illinois Road Map (Map). c. 1:918,720. Springfield: Illinois Secretary of State – via Illinois Digital Archives.