Illinois Route 73
Illinois Route 73 highlighted in red
Route information
Maintained by IDOT
Length	29.32 mi[1] (47.19 km)
Existed	1924[2]–present
Major junctions
South end	US 52 / IL 64 in Lanark
Major intersections	US 20 in Lena
North end	CTH M in Winslow
Location
Country	United States
State	Illinois
Counties	Carroll, Stephenson
Highway system
Illinois State Highway System Interstate US State Tollways Scenic
← IL 72 → I-74

Illinois Route 73 is a north–south state highway in northwest Illinois. It runs from the U.S. Route 52/Illinois Route 64 concurrency south of Lanark north to the Wisconsin border north of Winslow. This is a distance of 29.32 miles (47.19 km).^[1]

Route description

Illinois 73 is a two-lane surface road for its entire length. At its northern terminus, Illinois 73 becomes County Highway M in Green County, Wisconsin. This is the only Illinois state highway that does not either continue as another state highway, or end at a ferry crossing (current or former).^[2]

History

SBI Route 73 existed from Illinois Route 72 north of Lanark to Winslow. Around 1982, it replaced Illinois 72 from north of Lanark south to U.S. Route 52.^[2]

Major intersections

County	Location	mi[3]	km	Destinations	Notes
Carroll	Lanark	0.00	0.00	US 52 / IL 64 – Mount Carroll, Brookville	Southern terminus of IL 73
		4.2	6.8	IL 72 – Shannon	Western terminus of IL 72
Stephenson	Lena	18.1	29.1	US 20 – Stockton, Freeport
	Winslow	29.32	47.19	CTH-M – Martintown	Continuation into Wisconsin
1.000 mi = 1.609 km; 1.000 km = 0.621 mi