All of I-39 is US 51, since it was first built as 51 before receiving an Interstate designation late in the game. It's a useful Chicago bypass for traffic from St. Louis to Milwaukee or Madison.


As I start out NB, Central Illinois is wind farm country. "Busn." is IDOT standard abbreviation for what everyone else calls "Bus." The "Begin" sign is nice, but long after the beginning of the road, and just needs to say "39 North / Wisconsin" (and really, it should say "Rockford" as well).


Continuing north, Romans would be heading to 317. Peruvians would be herding 17 lllamas. This is why Illinois usually capitalizes its 'L's on these signs; the alternative is to put crossbars on the 'I'.


A railroad crosses the Illinois River in Peru, west of I-39. It's the 1893 LaSalle Railroad Bridge.


I-39's turn to cross the river, NB just northeast of the still-visible railroad bridge.


And now SB on the 1987 Abraham Lincoln Memorial Bridge, which I vote to call "The Abe." US 51 crossed west of here on IL 251 until then.


Looking east from Starved Rock.


More wind farm country north of Mendota and a complete lack of old signs on the entire highway lead me to photograph a routine repaving job NB nearing Rochelle as if it's extraordinary construction. Windmills then appear on the east side of the road for the first time.


I-39/US 51 NB hit US 20 south of Rockford. Originally planned to head into the city, with room for a modified cloverleaf if extended, I-39/US 51 instead head east to meet nearby I-90. I can't see the need for two parallel freeways, but maybe bringing US 51 off of the Tollway and into IL 251 north of downtown would be useful. As it is, I-39, which was born in 1984, wasn't extended along I-90 until 1996, and in that time the Illinois Tollway decided that its entire length is I-90. 39 gets very little attention, even with new signs like this ISTHA fractional milepost.

Continue south on US 51
IL 251, former US 51 along I-39

Into Wisconsin on I-39/90
Into Wisconsin on I-39 alone
To Ill 17
Onto I-90
Back to Illinois Roads
Back to Roads