| TITc Industries | Crystal Lake | IL | Fabricated Metal Product Manufacturing332811 | 100-499 | ◐ LIKELY ACTIVE |
| TLThe Label Printers LP | Aurora | IL | Printing and Related Support Activities323111 | 20-99 | ◐ LIKELY ACTIVE |
| TCTherafin Corporation | Frankfort | IL | Miscellaneous Manufacturing339113 | 20-99 | ◐ LIKELY ACTIVE |
| TZThree Z Printing CO | Teutopolis | IL | Printing and Related Support Activities323110 | 100-499 | ◐ LIKELY ACTIVE |
| TCThyssenkrupp Crankshaft CO | Danville | IL | Fabricated Metal Product Manufacturing332111 | 20-99 | ◐ LIKELY ACTIVE |
| TRTootsie Roll Industries LLC | Chicago | IL | Food Manufacturing311330 | 500+ | ◐ LIKELY ACTIVE |
| TDTop Die Casting CO | South Beloit | IL | Primary Metal Manufacturing331521 | 100-499 | ◐ LIKELY ACTIVE |
| TCTorkelson Cheese CO | Lena | IL | Food Manufacturing311513 | 1-19 | ◐ LIKELY ACTIVE |
| TATower Automotive Operations USA I LLC | Chicago | IL | Fabricated Metal Product Manufacturing332812 | 100-499 | ◐ LIKELY ACTIVE |
| TSTrelleborg Sealing Solutions, INC. | Streamwood | IL | Plastics and Rubber Products Manufacturing326130 | 20-99 | ◐ LIKELY ACTIVE |
| TCTri C CO INC | Eureka | IL | Fabricated Metal Product Manufacturing332710 | 1-19 | ◐ LIKELY ACTIVE |
| THTri-city Heat Treat CO | Rock Island | IL | Fabricated Metal Product Manufacturing332811 | 20-99 | ◐ LIKELY ACTIVE |
| TFTrio Foundry Inc | Montgomery | IL | Primary Metal Manufacturing331523 | 20-99 | ◐ LIKELY ACTIVE |
Tri-star Metals LLC | Freeport | IL | Primary Metal Manufacturing331222 | 100-499 | ◐ LIKELY ACTIVE |
| TNTrouw Nutrition USA Premix Plant | Highland | IL | Food Manufacturing311111 | 20-99 | ◐ LIKELY ACTIVE |
| TVTrue Value Manufacturing | Cary | IL | Chemical Manufacturing325510 | 100-499 | ◐ LIKELY ACTIVE |
| TBTwo Brothers Brewing Company | Warrenville | IL | Beverage and Tobacco Product Manufacturing312120 | 1-19 | ◐ LIKELY ACTIVE |
U Mark, INC | Belleville | IL | Miscellaneous Manufacturing339940 | 20-99 | ◐ LIKELY ACTIVE |
| UAUne Annee Brewery LLC | Niles | IL | Beverage and Tobacco Product Manufacturing312140 | 20-99 | ◐ LIKELY ACTIVE |
| UWUnified Wire and Cable, INC. | Dekalb | IL | Primary Metal Manufacturing331222 | 20-99 | ◐ LIKELY ACTIVE |
| UCUnilock Chicago | Aurora | IL | Nonmetallic Mineral Product Manufacturing327331 | 100-499 | ◐ LIKELY ACTIVE |
| USUnion Special CORP | Huntley | IL | Machinery Manufacturing333248 | 20-99 | ◐ LIKELY ACTIVE |
| UFUnited Foods | Chicago | IL | Food Manufacturing311612 | — | ◐ LIKELY ACTIVE |
| UGUnited Gasket CORP | Cicero | IL | Computer and Electronic Product Manufacturing334310 | 20-99 | ◐ LIKELY ACTIVE |
| ULUnited Laboratories INC | St Charles | IL | Chemical Manufacturing325611 | 100-499 | ◐ LIKELY ACTIVE |
| UMUnity Manufacturing CO | Chicago | IL | Electrical Equipment, Appliance & Component Manufacturing335110 | 20-99 | ◐ LIKELY ACTIVE |
| URUpm Raflatac INC Dixon Il | Dixon | IL | Paper Manufacturing322211 | 100-499 | ◐ LIKELY ACTIVE |
| UCUS Chrome CORP of Illinois | Kingston | IL | Fabricated Metal Product Manufacturing332813 | 20-99 | ◐ LIKELY ACTIVE |
| UCUtility Concrete Products | Morris | IL | Nonmetallic Mineral Product Manufacturing327320 | 100-499 | ◐ LIKELY ACTIVE |
| VFVanee Foods CO | Berkeley | IL | Food Manufacturing311422 | 100-499 | ◐ LIKELY ACTIVE |
| VOVantage Oleochemicals | Chicago | IL | Chemical Manufacturing325199 | 100-499 | ◐ LIKELY ACTIVE |
| VVVan Voorst Lumber CO INC | Union Hill | IL | Wood Product Manufacturing321920 | 20-99 | ◐ LIKELY ACTIVE |
| VIVarn International INC - a Flint Group CO | Batavia | IL | Chemical Manufacturing325612 | 1-19 | ◐ LIKELY ACTIVE |
| VFVermont Foundry CO | Vermont | IL | Primary Metal Manufacturing331522 | 20-99 | ◐ LIKELY ACTIVE |
Victor Envelope Company | Bensenville | IL | Paper Manufacturing322230 | 100-499 | ◐ LIKELY ACTIVE |
| VPViobin Products LLC | Monticello | IL | Food Manufacturing311211 | 20-99 | ◐ LIKELY ACTIVE |
| VIVvf Illinois Services LLC | Montgomery | IL | Chemical Manufacturing325611 | 100-499 | ◐ LIKELY ACTIVE |
| WTWauconda Tool & Engineering | Algonquin | IL | Fabricated Metal Product Manufacturing332119 | 20-99 | ◐ LIKELY ACTIVE |
| WTWheatland Tube CO - Chicago Div | Chicago | IL | Primary Metal Manufacturing331210 | 100-499 | ◐ LIKELY ACTIVE |
| WMWieland Metals INC | Wheeling | IL | Primary Metal Manufacturing331420 | 20-99 | ◐ LIKELY ACTIVE |
| WPWilliams-hayward Protective Coatings INC | Summit | IL | Chemical Manufacturing325510 | 20-99 | ◐ LIKELY ACTIVE |
| WHWilliams Healthcare Systems LLC | Elgin | IL | Fabricated Metal Product Manufacturing332813 | 1-19 | ◐ LIKELY ACTIVE |
| WMW. M. Plastics INC. | Mchenry | IL | Plastics and Rubber Products Manufacturing326199 | — | ◐ LIKELY ACTIVE |
| WWWm. W. Meyer & Sons INC | Libertyville | IL | Machinery Manufacturing333922 | 100-499 | ◐ LIKELY ACTIVE |
| WWWm W Nugent & CO INC | Skokie | IL | Fabricated Metal Product Manufacturing332420 | 20-99 | ◐ LIKELY ACTIVE |
| YMYetter Manufacturing CO INC | Colchester | IL | Fabricated Metal Product Manufacturing332999 | 20-99 | ◐ LIKELY ACTIVE |
| ZCZenith Cutter INC | Loves Park | IL | Fabricated Metal Product Manufacturing332721 | 20-99 | ◐ LIKELY ACTIVE |
| ATA-1 Tool CORP | Melrose Park | IL | Machinery Manufacturing333514 | 20-99 | ◐ LIKELY ACTIVE |
| AMAccent Metal Finishing INC | Schiller Park | IL | Fabricated Metal Product Manufacturing332813 | 1-19 | ◐ LIKELY ACTIVE |
| ACAccord Carton | Alsip | IL | Paper Manufacturing322212 | — | ◐ LIKELY ACTIVE |