Editing Interstate 39 (section)

== Route description ==
=== Illinois ===
[[File:Minonk,_Illinois_aerial_01A.jpg|left|thumb|Aerial view of I-39 as it passes [[Minonk, Illinois]], April&nbsp;2012]]
In Illinois, I-39 begins at [[Interstate 55 in Illinois|I-55]] north of [[Bloomington–Normal, Illinois]], less than one mile east from the intersection of I-74 and I-55 that runs around the city of Normal. US&nbsp;51 splits from I-55, joining I-39; exit&nbsp;2 marks the northern terminus of the [[U.S. Route 51 Business (Bloomington–Normal, Illinois)|US&nbsp;51 business route]]. From Normal northward, I-39 runs northward largely through rural areas. At exit&nbsp;8, the route forms the southern terminus of [[Illinois Route&nbsp;251]] (IL&nbsp;251), which was derived from the original routing of US&nbsp;51.

In [[Oglesby, Illinois|Oglesby]] in central [[LaSalle County, Illinois|LaSalle County]], I-39 passes next to [[Starved Rock State Park]], the busiest state park in Illinois. North of the park, it crosses the [[Illinois River]] over the [[Abraham Lincoln Memorial Bridge]]; at {{convert|1.3|mi|km}} long, it is the longest bridge in the state.<ref name="national_bridges2">{{cite web |author=Federal Highway Administration |title=Structure 000050019120847 |url=http://nationalbridges.com/index.php?option=com_lqm&b1849fc92c286e5b5ed0fbf618d953ae=1&task=showResults&query=8&lqm_id=169862&&format=raw&&Itemid=2 |url-status=dead |archive-url=https://web.archive.org/web/20140101034538/http://nationalbridges.com/index.php?option=com_lqm&b1849fc92c286e5b5ed0fbf618d953ae=1&task=showResults&query=8&lqm_id=169862&&format=raw&&Itemid=2 |archive-date=January 1, 2014 |access-date=June 1, 2012 |work=[[National Bridge Inventory]] |publisher=Federal Highway Administration}}</ref> Just north of the river, I-39 passes between the cities of [[LaSalle, Illinois|LaSalle]] and [[Peru, Illinois|Peru]]; as it intersects [[Interstate 80 in Illinois|I-80]] and [[U.S. Route 6 in Illinois|US&nbsp;6]], it makes its southernmost connections with the Chicago region. North of I-80, the wind turbines of the [[Mendota Hills Wind Farm]] (the first commercial wind farm in Illinois) can be seen from milepost&nbsp;72 at [[Mendota, Illinois|Mendota]] north to near [[Paw Paw, Illinois|Paw Paw]]. As I-39 continues northward, I-39 also intersects [[U.S. Route 52 in Illinois|US&nbsp;52]] and [[U.S. Route 30 in Illinois|US&nbsp;30]].

In [[Ogle County, Illinois|Ogle County]], I-39 intersects with [[Interstate 88 (Illinois)|I-88]] ([[Chicago–Kansas City Expressway|IL&nbsp;110]]), connecting I-39 to both Chicago and the Quad Cities regions. As it intersects [[Illinois Route 38|IL&nbsp;38]], [[Illinois Route 64|IL&nbsp;64]], and [[Illinois Route 72|IL&nbsp;72]], I-39 connects with the DeKalb–Sycamore region and far west suburbs of the Chicago area.

As I-39 crosses into Winnebago County, the Baxter Road exit (exit&nbsp;115) is the final exit before I-39 joins the [[U.S. Route 20 in Illinois|US&nbsp;20]] freeway bypass in Rockford. Approximately a mile east of the Alpine Road/US&nbsp;20 interchange, I-39 joins US&nbsp;20, moving from nearly entirely farmland to medium-density populated areas.

After heading northeast for approximately {{convert|4|mi|km|spell=in}}, US&nbsp;20 splits from I-39/US&nbsp;51; a mile northward, I-39/US&nbsp;51 runs concurrently with I-90 ([[Interstate 90 in Illinois#Jane Addams Memorial Tollway|Jane Addams Memorial Tollway]]). Though signed as I-39/I-90, the concurrency follows the mileposts of I-90. Though I-39 itself is not tolled, the [[Illinois Tollway]] collects tolls on the I-90 portion, including two ramp interchanges and an open-road toll plaza between Rockton and South Beloit.

At exit&nbsp;1 ([[Illinois Route 75|IL&nbsp;75]]) in [[South Beloit, Illinois|South Beloit]], US&nbsp;51 splits from I-39 to join IL&nbsp;75; {{convert|2|mi|km|spell=in}} westward, it continues the route of IL&nbsp;251 into Wisconsin. For all but one mile that I-39 is in Illinois, it runs concurrently with US&nbsp;51.{{clear left}}

=== Wisconsin ===
[[File:Interstate39NorthernWisconsinForest.jpg|left|thumb|I-39/US&nbsp;51 in northern Wisconsin]]
[[File:I39_northern_terminus.jpg|thumb|Northern terminus of I-39 at the interchange with WIS 29 near Wausau]]
I-39 enters Wisconsin in Rock County, concurrently with I-90. Bypassing Beloit to the east, it passes underneath the County Trunk Highway&nbsp;P bridge (CTH-P, Stateline Road). The tri-stack exit&nbsp;185 provides access to Beloit through [[Wisconsin Highway 81|WIS&nbsp;81]] and serves as the southern terminus of [[Interstate 43|I-43]] (accessing Milwaukee and Green Bay).<ref name="wisdot132">{{cite WisDOT map|year=2013}}</ref> The northernmost interchange serving the Beloit region is CTH-S (Shopiere Road) at exit&nbsp;183. About {{convert|7|mi|km|spell=in}} north of the I-43 interchange, I-39/I-90 is joined by [[Wisconsin Highway 11|WIS&nbsp;11]] for {{convert|2|mi|km|spell=in}} as it bypasses [[Janesville, Wisconsin|Janesville]]. In addition to the northern interchange that holds WIS&nbsp;11, Janesville is also accessed by [[U.S. Route 14 in Wisconsin|US&nbsp;14]] and [[Wisconsin Highway 26|WIS&nbsp;26]] (Milton Avenue). After crossing the [[Rock River (Mississippi River tributary)|Rock River]], I-39/I-90 has an interchange with [[Wisconsin Highway 59|WIS&nbsp;59]], connecting it with [[Edgerton, Wisconsin|Edgerton]] (to the west) and [[Milton, Wisconsin|Milton]] (to the southeast).<ref name="wisdot132" />

I-39 enters [[Dane County, Wisconsin|Dane County]] north of WIS&nbsp;59, passing west of [[Lake Koshkonong]]. For approximately {{convert|4|mi|km|spell=in}}, US&nbsp;51 rejoins the Interstate (from mile&nbsp;160 to 156) before it heads west through [[Stoughton, Wisconsin|Stoughton]]. I-39/I-90 changes direction north of [[Utica, Dane County, Wisconsin|Utica]], gradually turning northwest. At exit&nbsp;142, the highway turns returns north as it meets [[U.S. Route 12 in Wisconsin|US&nbsp;12]]/[[U.S. Route 18 in Wisconsin|US&nbsp;18]] in Madison, forming the eastern terminus of the Madison Beltline Highway; for approximately {{convert|650|ft|m}}, northbound I-39 is reduced to two lanes (for the first time since Cherry Valley, Illinois). North of the Beltline, I-39 accesses Madison through an interchange with [[Wisconsin Highway 30|WIS&nbsp;30]] and [[Interstate 94 in Wisconsin|I-94]] (routed from Milwaukee); the interchange is known as the Badger Interchange.<ref name="wisdot_badger_int2">{{cite press release |title=I-94 reconstruction to be discussed September 19 |publisher=Wisconsin Department of Transportation |url=http://www.dot.wisconsin.gov/opencms/export/nr/modules/news/news_0396.html_786229440.html |last=Buschkopf |first=Jim |access-date=January 12, 2007 |archive-url=https://web.archive.org/web/20080827230235/http://www.dot.wisconsin.gov/opencms/export/nr/modules/news/news_0396.html_786229440.html |archive-date=August 27, 2008}}</ref> {{convert|2|mi|km|spell=In}} further north, the highway has an interchange with [[U.S. Route 151|US&nbsp;151]] (splitting Madison and [[Sun Prairie, Wisconsin|Sun Prairie]]); the northernmost Madison-area I-39 interchanges are US&nbsp;51 (Madison and [[DeForest, Wisconsin|DeForest]]) and WIS&nbsp;19 (Sun Prairie and [[Waunakee, Wisconsin|Waunakee]]); CTH-V (West North Street) for DeForest serves as the last Dane County exit.

I-39/I-90/I-94 enters [[Columbia County, Wisconsin|Columbia County]] {{convert|4|mi|km|spell=in}} north-northwest of CTH-V.<ref name="wisdot132" /> From the county line northward, the highway returns to rural surroundings. {{Convert|3|mi|km|spell=In}} after crossing the [[Wisconsin River]], exit&nbsp;108 ([[Wisconsin Dells, Wisconsin|Wisconsin Dells]]) splits I-90/I-94 from I-39. For the first time since the US&nbsp;20 Bypass in Rockford–Cherry Valley, I-39 is four lanes instead of six or eight. I-39 continues northward from [[Wisconsin Highway 78|WIS&nbsp;78]] (which terminates at the interchange), routed towards Portage. I-39 connects with Portage through [[Wisconsin Highway 33|WIS&nbsp;33]], crosses the Wisconsin River a second time, connects with [[Wisconsin Highway 16|WIS&nbsp;16]]; a third interchange rejoins I-39 with US&nbsp;51. I-39 takes on the mileposts of the latter.

After taking on US&nbsp;51, I-39 continues northward, with few directional changes through [[Marquette County, Wisconsin|Marquette County]] and [[Waushara County, Wisconsin|Waushara County]]. In [[Portage County, Wisconsin|Portage County]], the highway continues its northward direction until it reaches the [[Stevens Point, Wisconsin|Stevens Point]] region, where it bypasses the city to the east and north; four interchanges connect with the city (CTH-HH, [[U.S. Route 10 in Wisconsin|US&nbsp;10]]/[[Wisconsin Highway 66|WIS&nbsp;66]], Stanley Street, and Bus. US&nbsp;51).

From Stevens Point northward, I-39 largely parallels the path of the Wisconsin River and Lake DuBay. Following its entrance into [[Marathon County, Wisconsin|Marathon County]], [[Wisconsin Highway 153|WIS&nbsp;153]] connects to I-39 in [[Mosinee, Wisconsin|Mosinee]], adjacent to the [[Central Wisconsin Airport]]. The final north-south interchange of I-39 is exit&nbsp;185 ([[U.S. Route 51 Business (Rothschild–Wausau, Wisconsin)|Bus. US&nbsp;51]]) in [[Rothschild, Wisconsin|Rothschild]], just before I-39 crosses the Wisconsin River.

I-39 ends with exit&nbsp;187, as [[Wisconsin Highway 29|WIS&nbsp;29]] merges with US&nbsp;51 (for approximately {{convert|4|mi|km|spell=in|disp=sqbr}}); the latter highway continues north to its terminus at US&nbsp;2 at the Wisconsin–Michigan border.{{clear left}}