Wisconsin Highway 78

State Trunk Highway 78
Route information
Maintained by WisDOT
Length:	92.83 mi (149.40 km)
Major junctions
South end:	IL 78 in Gratiot
	US 18 / US 151 in Mt. Horeb US 14 in Black Earth US 14 / WIS 19 in Mazomanie US 12 / WIS 60 in Sauk City
North end:	I-39 / I-90 / I-94 in Portage
Location
Counties:	Lafayette, Iowa, Green, Dane, Sauk, Columbia
Highway system
Wisconsin State Trunk Highway System Interstate U.S. State Byways Rustic ← WIS 77 WIS 79 →

State Trunk Highway 78 (often called Highway 78, STH 78 or WIS 78) is a state highway in the U.S. state of Wisconsin. It runs north–south in south central Wisconsin from Portage to the Illinois border near Gratiot.

Historical note: In the 1920s, Highway 78 was originally located on the Door County Peninsula on what is now Highway 57.