Interstate 39
Route information
Length:	306.14 mi[1] (492.68 km)
Major junctions
South end:	I-55 / US 51 in Normal, IL
	I-80 near La Salle, IL I-88 in Rochelle, IL I-90 near Rockford, IL I-43 near Beloit, WI I-94 near Madison, WI I-90 / I-94 near Portage, WI US 10 near Stevens Point, WI
North end:	US 51 / WIS 29 in Rothschild, WI
Highway system
Interstate Highway System Main • Auxiliary • Business ← IL 38 IL US 40 → ← WIS 38 WI WIS 39 →

Interstate 39 (I-39) is a highway in the midwestern United States. I-39 runs from Normal, Illinois at Interstate 55 to Highway 29 in Rothschild, Wisconsin, approximately six miles south of Wausau.^[2] I-39 was designed to replace US Highway 51, which in the early 1980s was one of the busiest two-lane highways in the United States. I-39 was built in the 1980s and 1990s.

In Illinois, the route has a total length of 140.82 miles (226.63 km).^[3] In Wisconsin, I-39 has a distance of 182 mi (293 km). With the exception of an eight-mile (13 km) segment around Portage, the Interstate shares a route with at least one other route number in the state. From Illinois to Portage, I-39 is concurrent with I-90. I-94 joins the pair in Madison until Portage. From Portage northward, US 51 is co-signed with the interstate. At 29 miles (47 km) in length, this concurrency of three Interstates is the longest in the country.

Route description[link]

Illinois[link]

Aerial view of Interstate 39 as it passes Minonk, Illinois. April 2012.

In Illinois, I-39 begins from Interstate 55 north of the Bloomington-Normal, Illinois, area alongside of Route 251. It runs north largely through rural areas from the city of Normal. About 55 miles (89 km) north of the city, I-39 crosses the Illinois River over the Abraham Lincoln Memorial Bridge, which is 2,170.8 metres (1.3 mi) long.^[4] Just north of the Illinois River, I-39 runs west of the cities of LaSalle and Peru before intersecting Interstate 80. North of I-80, the wind turbines of the Mendota Hills Wind Farm can be seen from milepost 72 at Mendota north to near Paw Paw. Further north I-39 runs along the south and east sides of Rockford, concurrent with U.S. 20. The interstate joins the Jane Addams Memorial Tollway and Interstate 90 near Cherry Valley, during which there is a toll booth in South Beloit. U.S. 51 leaves I-39/90 in South Beloit, while I-39/90 continue north into Wisconsin.

For all but 1 mile (2 km) that Interstate 39 is in Illinois, it is designated concurrently with U.S. Route 51. The southern terminus of I-39 is less than 1 mile (2 km) from Interstate 74 as it runs around Normal.

Wisconsin[link]

Interstate 39, along with U.S. 51, in northern Wisconsin

I-39 enters from Illinois along with I-90, passing under Stateline road, and bypasses Beloit to the east. East of the town, the route has a cloverleaf interchange that serves as the terminus for both WIS 81– which heads westward into Beloit– and I-43, which provides access to Milwaukee. The I-39/90 concurrency continues to the north and is joined by WIS 11 about 7 mi (11 km) north of the I-43 interchange. The route bypasses Janesville to the east, although interchanges with US 14 (where WIS 81 leaves the concurrency) and WIS 26 provide access to the town. The route continues generally to the north, crossing the Rock River before having an interchange with WIS 59 that provides access to Edgerton to the west.^[5] Subsequently, the route enters Dane County as it passes west of Lake Koshkonong. It is joined by US 51 and serves as the southern terminus of WIS 73. US 51 leaves the route 4 mi (6 km) to the north, about 7 mi (11 km) east of Stoughton. The Interstate gradually turns westward around Utica to an interchange with CTH N. It then turns gradually back to the north and interchanges with US 12 and US 18 in Madison. I-39 and I-90 bypass Madison to the east, and I-94 joins the concurrency at the eastern terminus of WIS 30, an interchange known as the Badger Interchange.^[6] About 2 mi (3 km) to the north, the highway crosses US 151, which includes a south-side access to High Crossing Boulevard. The last two Madison area interchanges are US 51 three miles (5 km) northwest of the US 151 interchange and WIS 19 another mile northwest of the US 51 interchange. Access is provided to CTH V just west of DeForest four miles (6 km) further north. I-39/I-90/I-94 enter Columbia County four miles (6 km) north-northwest of CTH V.^[7]

The Interstates cross WIS 60 at an interchange three miles (5 km) north of the county line west of Arlington and CTH CS at another interchange four miles (6 km) further north near Poynette. The highway crosses the Wisconsin River four miles (6 km) north of CTH CS. At three miles (5 km) further along the route from the river, I-39 leaves the concurrency with I-90 and I-94 and turns northward while the other two interstates turn northwest. WIS 78 terminates at this interchange and heads southwest. This is the starting point of the segment of freeway that carries the I-39 route alone. The interstate crosses WIS 33, the first of three interchanges accessing Portage, two miles (3 km) north of I-90/I-94. After crossing the Wisconsin River again, I-39 crosses the second interchange - this one with WIS 16 and turns northeast to an interchange with US 51. The US route joins the Interstate and both turn north once again and leave the Portage area and, after four miles (6 km), enter Marquette County.^[8]

WIS 23 joins I-39/US 51 northbound, 4 miles (6 km) from the county line. The three highways pass along Buffalo Lake and encounter a south-side half interchange with CTH D in the town of Packwaukee. WIS 23 leave the concurrency to the east at WIS 82 near Oxford. and the freeway takes a due north route to pass Westfield. I-39/US 51 enters Waushara County six miles (10 km) north of Westfield.^[9] Four miles north of the county line, I-39 / US 51 junction with WIS 21 in Coloma. I-39/US 51 meet an interchange in Hancock with CTH V five miles (8 km) further north and WIS 73 crosses in Plainfield after another five miles (8 km). This is two miles (3 km) south of the Portage County line.^[10] In Portage County, I-39/US 51 takes a straight due north trajectory which provides access to CTH D, CTH W and WIS 54 (also Business U.S. 51) over twelve miles (19 km). The WIS 54 interchange and the CTH B interchange a mile and a half north of it provide access for Plover. The next four interchanges - CTH HH, US 10 Eastbound / WIS 66 Westbound, Stanley Street and Business US 51 provide access to Stevens Point. Amongst these interchanges, the freeway turns northwestward, bypassing the city to the east and north. I-39/US 51 cross two more interchanges while in Portage County: Casimir Road four miles (6 km) northwest of Stevens Point,^[11] and Westbound US 10 two miles (3 km) north of Casimir Road. The freeway then parallels the Wisconsin River for six miles (10 km) to an Interchange with CTH DB east of Lake DuBay and one mile (1.6 km) south of the Marathon County line.^[12]

WIS 34 terminates at an interchange with I-39/US 51 in Knowlton three miles (5 km) northwest of the freeway's entry into Marathon County. The freeway turns due north from this interchange. WIS 153 crosses the freeway four miles further north in Mosinee. Maple Ridge Road crosses after another two miles (3 km) as the freeway turns northeastward into Rothschild.^[13] An interchange with Business US 51 is just south of the Wisconsin River crossing after four miles (6 km) from Maple Ridge Road. I-39 ends two miles (3 km) further north at the interchange with WIS 29 East just southwest of Wausau.^[14]

History[link]

Interstate 72 where Interstate 39 was supposed to have an interchange in Decatur

The genesis of Interstate 39 dates back to 1945, when the United States began planning the first 40,000 mile interstate system. An initial request was made for a north-south highway from South Beloit, Wisconsin to Salem, Illinois. and in 1956, legislation provided funding for the highway. However, the project was deemed a low priority and was shelved. During 1962 there were 531 crashes along U.S. 51 between Rockford and Decatur, with 11 fatlities. In 1969, the Illinois legislation started prompting the need for a highway in this corridor and the project was revived. When I-39 was being planned in the mid-1970s, it was to run from U.S Route 20 in Rockford to Interstate 57 near Salem, but only the area between Rockford and Decatur got the high priority funding.^[15] Due budgetary difficulties, I-39 only made it to Bloomington. U.S 51 was instead upgraded to a four-lane divided expressway between Bloomington and Decatur, with some traffic lights. When traveling on Interstate 72, between mileposts 139 and 140, one can see embankments for an expressway interchange that was never constructed, which was supposed to be where I-39 was to merge. At one time there were pavement stubs leading onto the embankments but they have since been removed. Interstate 39 was considered at one point for the unbuilt Peoria-to-Chicago Highway.

I-39 was established in 1984 on the section from Illinois Route 5 (now called Interstate 88) in Rochelle, to U.S. Route 20 in Rockford.^[16] I-39 was completed south from Route 5 to I-80 in 1986. By December 1987, construction on the section of I-39 between I-80 and Illinois Route 251 was finished. The next section, between Illinois Route 251 and Interstate 55 in Bloomington, opened in 1992, completing the southern part of I-39.^[17] In December 1989, the section from Bloomington to Hudson opened, a distance of about 4.4 miles (7.1 km)^[18] In early September 1992, another segment opened from IL 116 north to IL 17.^[19] Illinois Department of Transportation has not finished I-39, since its plans called for it to extend south to Decatur, Illinois. US 51 between Bloomington and Decatur has been improved to be a 4-lane divided highway with minimal stops.

In Wisconsin, the route was officially designated in 1992.^[20] In October 1993, AASHTO established part of I-39 in its northern section between Rockford and Rib Mountain, Wisconsin, then designated I-39 along existing portions of I-90, I-94, and U.S. Route 51. However, this part of the highway was not marked as I-39 for another four years, primarily because the Wisconsin Highway Department had to reconstruct the interchange connecting I-90 and I-94 with Wisconsin Highway 78 near Portage.^[21] Signs denoting I-39 were placed along the highway in Wisconsin until 1996, when the section between Portage and Rothschild, Wisconsin (near Wausau) received its signs.^[20] This occurred after then Governor Tommy Thompson designated the stretch between Portage and Wausau in 1996 after a five-year push to get the interstate designation approved.^[21] The remaining segment along I-90/I-94 was not signed for I-39 until late 1998^[20] The section between the I-90/I-94 interchange and US 51's interchange in Portage was previously a part of WIS 78. That route was truncated back to its current terminus when the Interstate's designation went into effect.^[22] The designation of I-39 violated Wisconsin's rule of not having any state trunkline number duplicated—Interstate, U.S. or state—as WIS 39 already existed.^[20]

Future[link]

As of October 2007, the Illinois Department of Transportation is in the preliminary design stages for a project involving reconstruction of I-39 from US 20 east to Harrison Avenue in Rockford. The goal of the project is to reconstruct ramps to modern-day standards, and allow southbound I-39 traffic to use through lanes at the US 20 interchange.^[23] Currently, southbound I-39 traffic must exit from the US 20 freeway.

Exit list[link]

This section contains a table that is missing mileposts for one or more junctions. Please help by adding the missing mileposts.

State	County	Location	Mile[24]	km	Exit[25]	Destinations	Notes
Illinois	McLean	Normal	0.0	0.0	—	I-55 / US 51 south to I-74 – Decatur, Chicago, Peoria, Champaign, St. Louis	South end of US 51 overlap
					2	US 51 Bus. – Bloomington, Normal
		Hudson			5	Hudson
					8	IL 251 (Lake Bloomington Road)
	Woodford	El Paso			14	US 24 – El Paso, Peoria
		Woodford			22	IL 116 – Peoria, Pontiac
		Minonk			27	Minonk
	Marshall	Wenona			35	IL 17 – Lacon, Wenona
	LaSalle	Lostant			41	IL 18 – Henry, Streator
		Tonica			48	Tonica
					51	IL 71 – Hennepin, Oglesby
					52	IL 251 – Peru, LaSalle
		Oglesby			54	Oglesby
		Illinois River			Abraham Lincoln Memorial Bridge
		La Salle			57	US 6 – LaSalle, Peru, Ottawa
					59	I-80 – LaSalle, Peru, Chicago, Des Moines	Signed as exits 59A (east) and 59B (west)
		Troy Grove			66	US 52 – Troy Grove
		Mendota			72	US 34 – Mendota, Earlville
	Lee	Paw Paw			82	Paw Paw
					87	US 30 – Sterling, Rock Falls, Aurora
		Steward			93	Steward
	Ogle	Rochelle			97	I-88 (Ronald Reagan Memorial Tollway) – Moline, Rock Island, Chicago	Signed as exits 97A (east) and 97B (west)
					99	IL 38 – DeKalb, Rochelle
					104	IL 64 – Sycamore, Oregon
		Monroe Center			111	IL 72 – Genoa, Byron
	Winnebago				115	Baxter Road
		Rockford				US 20 west – Freeport, Rockford	South end of US 20 overlap
		Cherry Valley			122A	US 20 east – Belvidere	North end of US 20 overlap
					122B	Harrison Avenue
						I-90 east (Jane Addams Memorial Tollway) – Chicago	South end of I-90 overlap; I-39 uses I-90's exit numbers from here north
		Rockford				US 20 Bus. (State Street)
						Riverside Boulevard	Northbound exit and tolled southbound entrance
						IL 173 (West Lane Road)	Northbound exit and tolled southbound entrance
		Rockton			South Beloit Toll Plaza
		South Beloit			3	Rockton Road (CR 9)
					1	US 51 north / IL 75 west – South Beloit	North end of US 51 overlap
					Illinois–Wisconsin state line
Wisconsin	Rock	Beloit			185B	I-43 north – Milwaukee
					185A	WIS 81 west – Beloit
					183	CTH-S (Shopiere Road)
					177	WIS 11 west – Janesville, Avalon	East end of WIS 11 overlap
		Janesville			174B	WIS 11 east (US 14 Bus. east) – Delavan	West end of WIS 11 overlap
					174A	Racine Street (US 14 Bus. west)
					171C	US 14 east
					171B	US 14 west / WIS 26 south – Janesville
					171A	WIS 26 north – Milton
					163	WIS 59 – Edgerton, Milton
	Dane				160	US 51 south / WIS 73 / WIS 106 – Edgerton
					156	US 51 north – Stoughton, Deerfield
					147	CTH-N – Stoughton, Cottage Grove
		Madison			142	US 12 / US 18 – Madison, Cambridge	Signed as exits 142A (west) and 142B (east)
					138B	WIS 30 west – Madison
					138A	I-94 east – Milwaukee	East end of I-94 overlap
					135C	High Crossing Boulevard	Westbound exit and eastbound entrance
					135B	US 151 north – Sun Prairie
					135A	US 151 south – Madison
					132	US 51 – Madison, De Forest
		Windsor			131	WIS 19 – Waunakee, Sun Prairie
					126	CTH-V – Dane, De Forest
	Columbia	Lodi			119	WIS 60 – Lodi, Arlington
					115	CTH-CS – Poynette, Lake Wisconsin
			79.14	127.36	84B	I-90 west / I-94 west – Wisconsin Dells	North end of I-90/I-94 overlap; exit 108B on I-90/I-94
			79.35	127.70	84A	WIS 78 south – Merrimac
		Portage	79.68	128.23	85	Cascade Mountain Road
			81.41	131.02	87	WIS 33 – Portage, Baraboo
			84.13	135.39	89	WIS 16 to WIS 127 – Portage, Wisconsin Dells	Signed as exits 89A (east) and 89B (west) northbound
			85.51	137.62	92	US 51 south – Portage	South end of US 51 overlap
	Marquette	Endeavour	94.12	151.47	100	WIS 23 west / CTH-P – Wisconsin Dells, Endeavor	South end of WIS 23 overlap
		Packwaukee	98.33	158.25	104	CTH-D – Packwaukee	Northbound exit and southbound entrance
			100.36	161.51	106	WIS 23 east / WIS 82 west – Oxford, Montello	North end of WIS 23 overlap
		Westfield	106.96	172.14	113	CTH-E / CTH-J – Westfield
	Waushara	Coloma	117.92	189.77	124	WIS 21 – Coloma, Necedah
		Hancock	125.09	201.31	131	CTH-V – Hancock
		Plainfield	130.64	210.24	136	WIS 73 – Plainfield, Wisconsin Rapids
	Portage		133.78	215.30	139	CTH-D – Almond
		Bancroft	137.26	220.90	143	CTH-W – Bancroft, Wisconsin Rapids
		Plover	145.63	234.37	151	WIS 54 / US 51 Bus. – Wisconsin Rapids, Plover, Waupaca
			147.27	237.01	153	CTH-B – Wisconsin Rapids, Plover, Amherst
		Whiting	150.20	241.72	156	CTH-HH – Whiting
		Stevens Point	152.43	245.31	158	US 10 east – Stevens Point, Waupaca, Appleton, Marshfield	Signed as exits 158A (east) and 158B (west) northbound; south end of US 10 overlap
		Hull	153.66	247.29	159	WIS 66 – Stevens Point, Rosholt
		Stevens Point	155.79	250.72	161	US 51 Bus. – Stevens Point
		Casimir	157.54	253.54	163	Casimir Road
			159.22	256.24	165	US 10 west – Marshfield	North end of US 10 overlap
			165.03	265.59	171	CTH-DB – Knowlton, Lake DuBay
	Marathon	Knowlton	169.31	272.48	175	WIS 34 – Knowlton, Wisconsin Rapids
		Mosinee	173.29	278.88	179	WIS 153 – Mosinee, Elderon
			175.15	281.88	181	Maple Ridge Road
		Rothschild	179.21	288.41	185	US 51 Bus. – Rothschild, Wausau, Schofield
			181.38	291.90	187	WIS 29 east – Weston, Green Bay	Currently, north end of I-39 ends immediately before interchange
			181.38	291.90	—	US 51 north / WIS 29 west – Wausau, Chippewa Falls	Northbound exit and southbound entrance; north end of US 51 overlap
1.000 mi = 1.609 km; 1.000 km = 0.621 mi      Concurrency terminus •      Closed/former •      Incomplete access •      Unopened

See also[link]

• Illinois portal
• U.S. Roads portal
• Wisconsin portal

References[link]

External links[link]

Wikimedia Commons has media related to: Interstate 39

• Illinois Highway Ends: Interstate 39

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