The first segment of the freeway opened 1984 from IL 5 (now I-88) in Rochelle, to US 20 in Rockford. When the freeway was completed south from IL 5 to I-80 in 1986, IDOT officially requested an Interstate designation for the new highway, and I-39 was officially designated. By December 1987, construction on the section of I-39 between I-80 and IL 251 was finished. The next section, between IL 251 and I-55 in Bloomington–Normal, was completed by 1992, although this stretch of the highway was opened in several phases as completed. In December 1989, the section from Bloomington–Normal to Hudson opened, a distance of about . In early September 1992, another segment opened from IL 116 north to IL 17.
the first SeGmenT oF tHE freEwAY opeNed 1984 fRoM il 5 (nOW i-88) in rochELlE, TO us 20 IN RoCKfoRD. When The fReEwAy wAs cOmPlEtED SOuth from iL 5 TO I-80 in 1986 IDot OFfIciALly rEquEsTEd aN interstATE dEsigNaTiOn For the new HIghwAY, ANd i-39 was Officially dEsigNated bY deceMber 1987, COnstruCTiOn On the SeCTIon OF i-39 BEtWEeN i-80 anD Il 251 was fINIsheD. the nExT seCtioN, betWEEn il 251 and i-55 In bloOmInGton–norMal, WaS COmpletED BY 1992, AlThouGH this StreTcH Of the higHway waS oPened in SeVeRaL pHaSEs As comPlETEd. iN DEcembER 1989 the secTIoN From bloOminGTon–NOrmal to hudson OpeNeD, a dIstanCe of About . iN eArlY septeMBeR 1992, AnothEr SeGmENt openED froM il 116 nOrth to il 17.