Interstate 43


Interstate 43 angles northeast from Beloit to Delavan, Elkhorn, Mukwonago and Milwaukee, then travels north along along the west shore of Lake Michigan to Kohler, Manitowoc before veering westward to Green Bay.

View of Leo Frigo Bridge from mouth of Fox River Photo taken by Peter Johnson (06/17/15).

Planned Improvements

Construction at Interstate 41 outside Green Bay is underway as part of the overall US 41 Project through Brown County. Work at the north end of Interstate 43 includes an upgrade of the substandard cloverleaf interchange into a high-speed directional T interchange. The southbound beginning of I-43 from I-41 will shift from a tight right-hand ramp onto a new directional ramp departing from the left. Work will also separate movements at the adjacent diamond interchange with U.S. 141 (Velp Avenue) and County Trunk Highway HS. Construction runs between September 2013 and December 2016.

A major revamp of the southern terminus, where Interstates 39, 90 and 94 come together with Wisconsin 81, is planned as part of the long term I-39/90 Expansion Project. Work will replace the current full-cloverleaf interchange with a semi/directional T interchange for interstate traffic and a diverging diamond (DDI) will handle movements to Wis 81. Construction is slated for 2018. See a rendering of the new interchange here.

Parallel U.S. Routes

Interstate 43 replaced U.S. 141 between Milwaukee and Green Bay. The route also doubles as U.S. 41 along the east-west leg of Interstates 894 and 41 in Milwaukee.


Interstate 43 was not an original 1956 Interstate Highway; it was commissioned in the 1970s along U.S. 141 as part of the Milwaukee-Green Bay Interstate Highway.1 Government planning maps of the Interstate Highway System from that era initially showed Interstate 43 as part of an extended Interstate 57, with presumably a long overlap along Interstate 94 from Chicago to Milwaukee (note that this overlap was never shown on any planning maps, so it would have been implied). Potential funding for the freeway in 1972 referenced the future Interstate as an extension of I-57 as well.5 The initial 82-mile route for I-57 was approved by the Federal Highway Administration in May 1973 between Saukville, northeast along U.S. 141, to Wisconsin 42, northwest of Sheboygan, and then northward to U.S. 151 outside Manitowoc. A northwesterly trajectory took I-57 from U.S. 151 to the planned Belleview interchange south of Green Bay. This route did not extend south of Saukville due to the controversial Cedarburg Bog area, with provisions made to tie the new I-57 in with the preexisting U.S. 141 freeway south of Saukville. The proposed new I-57 took it through Mequon and along the Wisconsin 57 corridor into Milwaukee otherwise.6

However, the Milwaukee-Green Bay Interstate was soon designated as a distinct route (numbered Interstate 43) and the southern terminus was located at the current junction between Interstates 94 and 794 (Marquette Interchange) in Downtown Milwaukee. The existing U.S. 141 freeway in north Milwaukee became part of I-43; the Interstate was then extended north toward Green Bay. Construction of this portion of the route was completed in 1981.1

Meanwhile, what was originally designated as Wisconsin 15 (via the Rock Freeway, which connected Beloit with Milwaukee) began construction in 1969 and was completed in 1976. Approximately ten years later, on November 24, 1987, the highway was added to Interstate 43. With this action, I-43 gained 72 miles to the southwest along Wisconsin 15 / Rock Freeway to Interstate 90 near the state line.1 Wisconsin 15 was decommissioned by this action. With the extension of Interstate 39 into Wisconsin on October 16, 1992, I-43 connected to I-39. Signs for Interstate 39 were mostly erected around 1996.

For more information, visit Chris Bessert's Wisconsin Highways: Interstate 43 page. This page also includes a discussion of the proposed location of the "Milwaukee to Green Bay Interstate Highway," including consideration for what is now Interstate 41 as a candidate for the path of I-43 in the early planning stages.

Southern Terminus - Interstates 39 and 90 - Beloit, Wisconsin
Perspective from Interstate 43 west
Crossing over Schroeder Road, travelers along I-43 south see the first guide sign for Exits 1B/A with Interstates 39 and 90. All signage for the full cloverleaf interchange omitted the 1993 extension of I-39 northward into Wisconsin from Rockford, Illinois. This should be rectified with the interchange revamp starting in 2018. Photo taken 05/30/11.
Departing from the diamond interchange with Hart Road, Interstate 43 progresses one mile west to Interstates 39 & 90. I-39 & 90 lead south three miles to cross the Illinois state line and north ten miles to Janesville. Photo taken 05/06/10.
An end shield precedes the ramp departures for Interstates 39 and 90 and the I-43 transition into Wisconsin 81, a commercial arterial extending west into Beloit. Photo taken 05/06/10.
Exit 1B leaves Interstate 43 south for I-39 north & 90 west to Madison. Construction through 2023 upgrades the corridor to six overall lanes. Photo taken 05/06/10.
Interstate 43 south reaches the loop ramp (Exit 1A) for I-39 south & 90 east to Rockford, Chicago, Bloomington and Normal. Wisconsin 81 commences a nearly 124-mile route to Wisconsin 133 at Cassville here. Photo taken 05/06/10.
Historical Perspective from Interstate 43 south
Prominent freeway ends signage advised motorists of the pending terminus of Interstate 43. Similar signage was found at the original southern terminus of Interstate 69 at Indianapolis. Photo taken by Chris Lokken and Sage Sulenta (04/14/07).
A pair of end shields were posted for Interstate 43 as motorists entered the cloverleaf interchange (Exits 1B/A) with Interstates 39 & 90 and Wisconsin 81 (Milwaukee Road) west. These assemblies were later replaced with a solo set of shields that included junction I-39. Photo taken by Brian Down (12/02).
Perspective from Wisconsin 81 east
Wisconsin 81 end shield assembly posted ahead of the arterial transition into Interstate 43. A signalized intersection lies ahead with Ford Drive north and Freeman Parkway south, local roads serving adjacent businesses and subdivisions. Photo taken 05/06/10.
Supplemental signs were added to reflect the Interstate 39 extension north from Rockford, Illinois to Wausau, Wisconsin. I-39 combines with I-90 east to the south side of Rockford, where it shifts westward for the eventual pairing with U.S. 51 to Lasalle, Peru and Normal. Photo taken 05/06/10.
Heading south from Beloit, Interstates 39 & 90 transition into the tolled Jane Addams Memorial (Northwest) Tollway. The tandem combine with U.S. 51 in six miles and split in 20 miles ahead of U.S. 20. I-90 remains tolled leading southeast to Chicago. Photo taken 05/09/10.
Perspective from Interstate 43 north
A shield assembly references Interstate 39 for the approaching loop ramp (Exit 1B) onto I-39 north & 90 west to Janesville and Madison. Photo taken 05/06/10.
Interstates 39 & 90 lead north 45 miles to the capital city of Madison, where I-94 ties in for a three-way overlap to Portage. Photo taken 05/06/10.
Millington Road forms a south side frontage road to Interstate 43 as motorists pass by the first northbound reassurance marker. The freeway doubles as an Alternate route for I-39 through to Exit 6 with Wis 140. Photo taken 05/06/10.
Historical Perspective from Wisconsin 81 east
Interstate 39 was finally added to this assembly after 2007, 14 years after the extension north from Rockford, Illinois to Wausau was made official by AASHTO. Photo taken by Chris Lokken and Sage Sulenta (04/14/07).
Perspective from Interstates 39 north & 90 west
Just beyond the Illinois state line, Interstates 39 north & 90 west travel to within two miles of Interstate 43 and Wisconsin 81. A rest area precedes the cloverleaf interchange. Photo taken 05/06/10.
Cranston Road spans Interstates 39 & 90 one mile ahead of Exit 185B for Interstate 43 north. The freeway remains rural as it encircles the eastern outskirts of Beloit. Photo taken 05/06/10.
The northbound beginning of Interstate 43 departs I-39 north & 90 west via Exit 185B. I-43 serves the cities of Delavan, Elkhorn, and Waukesha on its northeasterly trek toward Milwaukee. The freeway reaches I-41 & 894 in 60 miles. Photo taken 05/06/10.
Perspective from Interstates 39 south & 90 east
Forthcoming Exit 185 with Interstate 43 north and Wisconsin 81 south provides the second of two interchanges serving the city of Beloit on I-39 south & 90 east. The full cloverleaf interchange with I-43 north lies one mile south of the Hart Road overpass here. Photo taken 05/06/10.
Exit 185A departs I-39 south & 90 west for Wisconsin 81 (Milwaukee Road) west. The Trunk Highway extends west from the ending I-43 toward Downtown Beloit to the straddle southern reaches of Wisconsin westward to Cassville along the Mississippi River. Photo taken 05/06/10.
A full guide sign takes the place of a conventional gore point sign as Exit 185B loops away from I-39 south & 90 east for Interstate 43 north. I-43 travels a rural route to Mukwonago, where transitions to a commuter route leading into Milwaukee, 64 miles to the northeast. Photo taken 05/06/10.
Northern Terminus - U.S. 41-141 - Howard, Wisconsin
Perspective from Interstate 43 north
The penultimate interchange is with Atkinson Drive, followed by the junction with U.S. 41-141. The tied arch bridge in the background is Interstate 43's high-level bridge over the Fox River. Called the Leo Frigo Memorial (Tower Drive) Bridge,2 it carries Interstate 43 approximately 120 feet above the high water level of the Fox River, which allows for large ships to pass under the freeway. Photo taken by Chris Lokken and Sage Sulenta (04/14/07).
Ascending up the Leo Frigo Memorial (Tower Drive) Bridge over the Fox River on Interstate 43 north, the view from is spectacular. From here, one can see downtown Green Bay, Lake Michigan/Green Bay, and Lambeau Field (home of the Green Bay Packers of the National Football League). However, the bridge is the location of suicide attempts, and some are requesting a fence be erected on the bridge to prevent jumps, especially after a high-profile suicide attempt from July 2004.3 Photo taken by Chris Lokken and Sage Sulenta (04/14/07).
The last North I-43 reassurance sign posted after Atkinson Avenue. Photo taken by Peter Johnson (06/17/15).
One mile ahead of Interstate 41 & U.S. 141 along Interstate 43 north. Interstate 41 runs south from Ashwaubenon to Appleton. U.S. 141 travels north to Iron Mountain, Michigan, and U.S. 41 follows the shoreline of Green Bay north to Marinette and Menominee, Michigan. Photo taken by Peter Johnson (11/05/15).
A new end sign for Interstate 43 was installed during September 2015. Photo taken by Peter Johnson (11/03/15).
The new I-43 north to I-41 south ramp will open in fall 2016. Until then, drivers are detoured north onto I-41 & U.S. 41-141 to Lineville Road for a U-turn to make the connection while the southbound lanes of Interstate 41 are rebuilt. Photo taken by Peter Johnson (11/03/15).
Traffic split between I-41 South and U.S. 41/U.S. 141 north. A directional T interchange is replacing the old folded diamond interchange. Photo taken by Peter Johnson (06/17/15).
Historical Perspective from Interstate 43 north
One mile ahead of then U.S. 41 & 141 (Exits 192A/B) on I-43 north near Ken Euers Nature Area. Photo taken by Chris Lokken and Sage Sulenta (04/14/07).
This sign bridge was next in line for Interstate 43 north traffic. One lane was allocated for each direction of U.S. 41-141. Note how U.S. 141 south was omitted from the southbound sign. This was due to U.S. 141 south exiting almost immediately after Interstate 43's northern terminus. Photo taken by Chris Lokken and Sage Sulenta (04/14/07).
A pair of END shields for Interstate 43 were posted just beyond the Military Avenue overpass. The scene is now where the southbound flyover to Interstate 41 & U.S. 41-141 departs. Photos taken by Jeff Royston (10/00) and Chris Lokken and Sage Sulenta (04/14/07).
Traffic for U.S. 41 and U.S. 141 north to Marinette and Iron Mountain, Michigan departed at Exit 192A. Photo taken 08/12/09.
Continuing on the ramp to U.S. 41 and U.S. 141 south was this reassurance shield assembly (similar to how IowaDOT signs the Interstate to Interstate connections). A tight curve was just ahead. A new flyover replaces the movement by fall 2016. When the new flyover ramp is complete, traffic from I-43 north will not be able to access US 141 south. Photo taken by Chris Lokken and Sage Sulenta (04/14/07).
A return to the former loop ramp for I-41 & U.S. 141 south from I-43 north revealed an I-41 shield assembly. This ramp closed permanently in October 2015 as part of a project to rebuild the southbound lanes of Interstate 41. Photo taken by Peter Johnson (06/17/15).
A tight loop ramp connected Interstate 43 north with U.S. 41-141 south. This movement was replaced by a high speed flyover. Photo taken by Chris Lokken and Sage Sulenta (04/14/07).
Historical Perspective from U.S. 41 & 141 south
One mile north of Interstate 43 south along U.S. 41-141 southbound. Interstate 43 serves the immediate waterfront area of Green Bay before encircling the east side, while Interstate 41 & U.S. 41 stays on the west side of the city. U.S. 141 leaves U.S. 41 shortly after this interchange to serve Downtown Green Bay via surface streets. Photo taken 05/30/11.
Traffic departed U.S. 41 & 141 for the southbound beginning of Interstate 43 at Exit 171. Originally a rather tight ramp facilitated movement to I-43 (hence the 30 mph sign).
I-41 & U.S. 41 connects Green Bay with the Fox Valley Cities of Appleton and Oshkosh. I-43 provides the quicker connection to Milwaukee from Green Bay and thus gets it for the control point. Interstate 43 also serves Sheboygan and Manitowoc. Photo taken 05/30/11.
After traffic from Interstate 43 north merged onto U.S. 41 & 141 south, Exit 170 quickly departed for Velp Avenue. U.S. 141 heads to Downtown Green Bay via Velp Avenue and Main Street before ending at I-43 just southeast of Green Bay. Previously, U.S. 141 continued south to Milwaukee, but it was replaced by Interstate 43 during the 1970s as the freeway was constructed. U.S. 141 was retracted out of Milwaukee to Grafton in 1977, Port Washington in 1979, Sheboygan in 1980, and Bellevue (current southern terminus) in 1981.4 Photo taken by Chris Lokken and Sage Sulenta (04/14/07).
Perspective from Interstate 41 & U.S. 41 north
Temporary shields posted at the Memorial Drive underpass for the upcoming back to back ramps for U.S. 141 south and CTH HS (Velp Avenue) north and I-43 south. Photo taken by Peter Johnson (11/03/15).
The flyover ramp for I-43 & U.S. 141 south from Interstate 41 north opened on August 27, 2015. Photo taken by Peter Johnson (11/03/15).
Temporary sign marking the exit to Interstate 43 south, U.S. 141 north and CTH HS (Velp Avenue). Photo taken by Peter Johnson (11/03/15).
A reassurance marker for Interstate 43 stands along the flyover ramp carrying traffic from Interstate 41 north via Exit 170B. Photo taken by Peter Johnson (11/03/15).
Historical Perspective from U.S. 41 north
Traveling north on U.S. 41 as it passed through the Velp Avenue interchange, the next exit was Exit 171, Interstate 43 south to Milwaukee. This was the first mention of the interchange with I-43's northern terminus on U.S. 41 north. U.S. 141 north has yet to merge in. Photo taken 05/30/11.
This sign bridge was located at the split of traffic between U.S. 41 & 141 north and Interstate 43's southbound beginning. I-43 serves Downtown Green Bay before reaching Wisconsin 54 and Wisconsin 57, which provide an easy link to Door County. Otherwise, Interstate 43 turns to the south towards Sheboygan and Milwaukee. Meanwhile, U.S. 41 and U.S. 141 head north via a freeway to Abrams before separating to head to Marinette (U.S. 41) and Iron Mountain, Michigan (U.S. 141).
This loop ramp was replaced by a new directional ramp during road work between 2013-16. Photo taken 05/30/11.
Perspective from Interstate 43 south
The first reassurance shield for Interstate 43 south, posted just after the new ramp from I-41 north to I-43 south opened on August 28, 2015. Photo taken by Peter Johnson (11/03/15).


  1. Wisconsin Highways: Highways 40-49, Chris Bessert.
  2. State of Wisconsin Statutes: Chapter 84, State Trunk Highways (Federal Aid) - Section 84.1033 states as follows: "Leo Frigo Memorial Bridge. No later than 6 months after May 9, 2002, the department shall designate and mark the bridge on I 43 across the Fox River in the city of Green Bay as the "Leo Frigo Memorial Bridge" in recognition and appreciation of Leo Frigo, a civic and philanthropic leader in the Green Bay area whose legacy includes one of the largest food pantry programs in the nation for feeding the hungry."
  3. "Local Trooper is National Hero." WBAY-TV (Channel 2) Green Bay, July 19, 2004.
  4. U.S. Highway 141 by Robert V. Droz.
  5. "I-57 Fund Extension Appears Probable." The Milwaukee Journal, October 7, 1972.
  6. "Route Approved for I-57." The Milwaukee Journal, May 18, 1973.
  7. "Final investigative report from Leo Frigo Bridge sagging released." Fox 11 News, May 18, 2015.
  8. Wisconsin Highways: Highways 140-149, Chris Bessert.

Page Updated November 6, 2015.

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State Wisconsin
Mileage 191.55
Cities Beloit, Delavan, Milwaukee, Sheboygan, Manitowoc, Green Bay
Junctions Interstate 39/Interstate 90, Interstate 894, Interstate 94/Interstate 894, Interstate 94/Interstate 794
Source: December 31, 2014 Interstate Route Log and Finders List
I-43 south approaching the top of Leo Frigo Bridge in Green Bay. Photo taken by Peter Johnson (06/17/15).
The Lego Frigo Bridge spans the Fox River near its mouth on Green Bay. A portion of the arch bridge sagged on September 25, 2013, leading to a three-month plus emergency closure for repairs. WisDOT indicated that soil conditions corroded steel pilings, causing one to buckle and a pier to sink. Measures were taken during the $15 million repair project to prevent corrosion for a 75 year period.
Looking west from the Ken Euers Nature Area at the interchange between Interstates 41, 43 and U.S. 41 and 141. Photo taken by Peter Johnson (10/22/15).
The ramps from I-41 south to I-43 south and I-43 south to I-41 south closed on October 23, 2015. The last phase of the I-41 Project will reopen those connections along new ramps in September 2016.
The initial stretch of what would eventually become a part of Interstate 43 appears on this 1962 map of Milwaukee.
The first portion of U.S. 141 upgraded to the North-South Freeway in Milwaukee ran north from Wisconsin 190 (Capitol Drive) to County Trunk Highway PP (Good Hope Road). This stretch was completed in 1963.8
Interstate 43 debuted on the 1975 edition of the Rand McNally North American Road Atlas.
Interstate 43 was posted in 1975 along the U.S. 141 freeway from Interstate 94 in Milwaukee to Wisconsin 23 at Sheboygan. U.S. 141 was truncated northward to Grafton by 1977.8