State Trunk Highway 30 (often called Highway 30, STH-30 or WIS 30) is a state highway in the U.S. state of Wisconsin. It runs east–west in suburban Madison as a connector freeway between Interstate 39, Interstate 90, and Interstate 94 at the Badger Interchange to US 151 east of Downtown Madison. This section is all that remains of the highway that stood as of 1964 after I-94 was commissioned. This is the second alignment of the route number - the first beginning in Platteville and ending in Readstown.

WIS 30 is a freeway for its entire length and lies completely within the city of Madison. It junctions with US 151 at a folded diamond interchange. West of the terminus, the road becomes Aberg Avenue which provides a shortcut to WIS 113 north, providing a near-direct through route to Dane County Regional Airport to the north via International Lane. WIS 30 has three interchanges between termini: one at Fair Oaks Avenue, one at Stoughton Road (US 51) and a half-diamond at North Thompson Drive (CTH-T). The Thompson Drive interchange features roundabouts at the ramp junctions with the crossing street. WIS 30 ends at its junction with Interstates 39, 90 and 94 at what is commonly known as the Badger Interchange. The roadway continues as Interstate 94 east, heading towards Milwaukee. The interchanges are numbered sequentially from west to east.

From 1924 until the completion of I-94 between Madison and Milwaukee, WIS 30 ran from the Wisconsin State Capitol from King Street east to Wisconsin Avenue in downtown Milwaukee, along with WIS 19. The route of WIS 30 had several different alignments during that time, all which generally parallel the current routing of I-94.

WIS 30 was the main route between the two largest cities in the state until I-94's completion in the late 1960s.

The entire highway is in Madison, Dane County.

mi	km	Exit	Destinations	Notes
0.00	0.00	1A	US 151 (East Washington Avenue)	Western terminus; road continues as Aberg Avenue
0.26	0.42	1B	Fair Oaks Avenue
0.5	0.80	1C	US 51 (Stoughton Road)
1.4	2.3	2	CTH-T (Thompson Drive)	Eastbound exit and westbound entrance
2.1	3.4	3A	I-39 south / I-90 east – Janesville, Chicago	Left exit signed as exit 240A westbound, left entrance eastbound; I-90 west exits 138A-B
		3B	I-39 north / I-90 west / I-94 west – Wisconsin Dells	Eastbound left exit and westbound entrance; I-90 east exit 138B
2.3	3.7		I-94 east – Milwaukee	Eastern terminus; I-94 exit 240
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Incomplete access

• U.S. Roads portal

• Media related to Wisconsin Highway 30 at Wikimedia Commons