US 12 crosses the St. Croix River from Minnesota concurrent with I-94 into St. Croix County. Wisconsin Highway 35 (WIS 35) joins both routes upon their entry into Wisconsin and exits south three miles (4.8 km) east. US 12 leaves I-94 one mile (1.6 km) further east from the eastern WIS 35 exit, treks two miles (3.2 km) north, and parallels the Interstate. The highway crosses WIS 65 in Roberts and passes through Hammond over a 15-mile (24 km) segment to Baldwin, where it crosses US 63. US 12 passes through Woodville four miles (6.4 km) east of Baldwin and crosses WIS 128 in Wilson, two miles (3.2 km) west of the Dunn County line.[2] Roughly three miles (4.8 km) into Dunn County, US 12 passes through Knapp then turns southeastward, connecting with WIS 79 six miles (9.7 km) further; it then joins WIS 25 (North Broadway Street) to the south in Menomonie. US 12 turns east onto WIS 29 (Main Street East) in downtown Menomonie, and the two routes follow Stout Road east out of the city.[3] The highways meet an interchange with I-94, then split one half of a mile (0.80 km) east in Elk Mound at the junction with WIS 40. US 12 passes through Elk Mound and enters Eau Claire County.[4]
US 12 and WIS 27 cross WIS 95 in Merrillan and WIS 54 in Black River Falls. US 12 and WIS 27 also split in Black River Falls. US 12 follows I-94 to the southeast past Millston and into Monroe County.[8] The highway crosses I-94 (with no access) south of Kirby and junctions with WIS 21 on the north side of Tomah at an interchange with the Interstate. US 12 passes through Tomah and joins with WIS 16 on the south side at the junction with WIS 131 near Mill Bluff State Park. The highways continue paralleling I-90 and I-94 southeast and pass through Oakdale and into Juneau County.[8]
At the I-90/94 interchange, US 12 becomes a freeway that bypasses Baraboo that goes just south of the Grasser Road overpass. The highway becomes an expressway just north of Lehman Road and remains so until a few miles north of Sauk City. WIS 60 briefly joins US 12 in Sauk City and WIS 78 crosses the Wisconsin River concurrently with US 12 into Dane County.[14] US 12 becomes an expressway again at the county line and continues southeast, crossing WIS 19 at Springfield Corners. Just northwest of Middleton, the route becomes a freeway as it enters the Madison area along the West Beltline Highway.[15]
US 12 merges with US 14 at University Avenue. The freeway continues south and passes the interchanges of Greenway Blvd, Old Sauk Road, and Mineral Point Road (CTH-S). The freeway then turns eastward and passes the interchanges of Gammon Road, Whitney Way, and Verona Road/Midvale Blvd, where US 151 and US 18 join the freeway, creating a concurrency of four US Highways for a few miles. During the four-way concurrency, the freeway passes the interchange of Seminole Highway (only accessible from the westbound side), the University of Wisconsin–Madison Arboretum, and the interchanges of Todd Drive, Fish Hatchery Road (CTH-D), and Park Street, where US 14 leaves to go south and US 151 north into downtown Madison. Until 2007, the four-way concurrency had a grade level railroad crossing between Todd Drive and Fish Hatchery Road. The freeway also had several ramps, which contained driveways that accessed businesses.[16] US 12 and US 18 continue east into Monona and cross the Upper Mud Lake channel. The highways meet US 51 at Stoughton Road, then interchange with I-39 and I-90 on the southeast side of Madison.[17] US 12 and US 18 continue as an expressway east of the Interstates, junctioning with WIS 73 in Deerfield and splitting, with US 12 turning southeast into Jefferson County in Cambridge.[15]
Cambridge to Genoa City
After leaving Cambridge, US 12 passes through Oakland and crosses WIS 26, WIS 89, and WIS 106 in Fort Atkinson. WIS 89 joins US 12 as the route turns southward to approach Whitewater, bypassing the city to the south into Walworth County. The route briefly enters Rock County before crossing into Walworth County.[18] WIS 89 turns off US 12 at its junction with WIS 59. WIS 59 East follows US 12 briefly before turning north into the city. US 12 passes through La Grange and turns south at the junction with WIS 20 to follow WIS 67 south. US 12 turns southeast off WIS 67 onto a freeway northeast of Elkhorn. The highway crosses over WIS 11 with no access (although access is provided via nearby I-43), then interchanges with I-43. Access for Lake Geneva is provided at WIS 120 and WIS 50 as US 12 passes the city to the east. The highway turns south into Genoa City, where the freeway ends and US 12 follows the crossroad into Illinois.
The entire route was originally signed as WIS 12 in 1917 prior to the creation of the U.S. Numbered Highway System in 1926. Aside from changes resulting from the construction of freeways and US 12 being aligned on them, some differences exist between the original route and today's alignment. WIS 12 followed CTH-E, a more southerly alignment, between Menomonie and Eau Claire. From Black River Falls, WIS 12 continued south to Shamrock and turned east to follow CTH-O to Millston. WIS 12 ran southerly from Tomah along WIS 131 to CTH-A and turned east onto the county road to pass through Hustler and Clifton to reach New Lisbon.[1][19]
The state originally planned to widen all of US 12 from Genoa City to Madison to freeway in anticipation of the Illinois Tollway building out a northwest toll road from Chicago to replace the original US 12 right of way. The plans were reeled back as WisDOT started widening between Elkhorn and Genoa City, as community and environmental opposition effectively shelved the planned toll expressway south of the border.
Despite that, WisDOT continued to re-route Cambridge and Whitewater to a direct and flatter roadbed. A two-lane bypass of Whitewater was added in 2005. Widening US 12 between Middleton and Sauk City was completed in 2005, but local opposition prevented most of the remaining route north of that point to Lake Delton from being constructed.[1]
In 1995 a grade crossing with the Illinois Central Railroad on the Madison Beltline between the Verona Road and Whitney Way interchanges was removed.[citation needed]
In 2007, a by-then abandoned grade crossing with the Chicago and North Western Railroad on the Beltline in Madison between the Todd Drive and Fish Hatchery Road interchanges was removed as part of a Beltline rehabilitation project. Until then the crossing was isolated with Jersey barriers.[20]
In Wisconsin, the highway was designated as the Iron Brigade Memorial Highway in 1993 to honor the Civil War Union Army unit; it also has this designation in Michigan, Indiana, and Illinois.[21][22][23][24]
Future
The portion of US 12 between Parmenter Street (the end of the Madison Beltline) to WIS 78/188 is being studied for future freeway conversion in two separate studies.[25][26] Additionally, WisDOT has long range plans for freeway conversion between the Baraboo bypass and WIS 78/188, including a bypass of Sauk City, however, there is no timetable.[27]
Major intersections
This section is missing mileposts for junctions. Please help by adding them.
^Wisconsin Department of Transportation (January 2014). Dunn Co(PDF) (Map). 1:100,000. Madison: Wisconsin Department of Transportation. Archived from the original(PDF) on October 30, 2014. Retrieved June 8, 2015.
^Wisconsin Department of Transportation (January 2014). Eau Claire Co(PDF) (Map). 1:100,000. Madison: Wisconsin Department of Transportation. Retrieved June 8, 2015.
^Wisconsin Department of Transportation (January 2014). Clark Co(PDF) (Map). 1:100,000. Madison: Wisconsin Department of Transportation. Archived from the original(PDF) on May 16, 2008. Retrieved June 8, 2015.
^ abWisconsin Department of Transportation (January 2014). Monroe Co(PDF) (Map). 1:100,000. Madison: Wisconsin Department of Transportation. Archived from the original(PDF) on April 13, 2007. Retrieved June 8, 2015.
^Wisconsin Department of Transportation (January 2014). Juneau Co(PDF) (Map). 1:100,000. Madison: Wisconsin Department of Transportation. Archived from the original(PDF) on April 13, 2007. Retrieved June 8, 2015.
^ abWisconsin Department of Transportation (January 2014). Sauk Co(PDF) (Map). 1:100,000. Madison: Wisconsin Department of Transportation. Archived from the original(PDF) on February 21, 2015. Retrieved June 8, 2015.
^ abWisconsin Department of Transportation (January 2014). Dane Co(PDF) (Map). 1:100,000. Madison: Wisconsin Department of Transportation. Archived from the original(PDF) on June 14, 2011. Retrieved June 8, 2015.
^Wisconsin Department of Transportation (January 2014). Jefferson Co(PDF) (Map). 1:100,000. Madison: Wisconsin Department of Transportation. Archived from the original(PDF) on April 13, 2007. Retrieved June 8, 2015.
^Wisconsin Department of Transportation (June 4, 2010). "Commemorative Highways and Bridges". Wisconsin Department of Transportation. Retrieved August 15, 2012.
^Wisconsin Department of Transportation Southwest Region. "US 12 Freeway Conversion Study". Wisconsin Department of Transportation. Retrieved June 8, 2015.
^Wisconsin Department of Transportation Southwest Region. "US 12 Corridor Study". Wisconsin Department of Transportation. Retrieved June 8, 2015.
^Village of Prairie du Sac; Town of Prairie du Sac; Village of Sauk City (June 26, 2012). "Highway 12/PF and Airport Area Plan"(PDF). Village of Prairie du Sac, Wisconsin. Retrieved June 8, 2015.
^Wisconsin Department of Transportation. "Exit Numbers on US 12". Wisconsin Department of Transportation. Retrieved June 10, 2007.