| CPCreative Printing Service INC | Des Plaines | IL | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
| CMCr Marble INC | Champaign | IL | Plastics and Rubber Products Manufacturing326191 | — | ◇ UNVERIFIED |
| CCCronus Chemicals LLC | Tuscola | IL | Chemical Manufacturing325311 | — | ◇ UNVERIFIED |
| CCCross Construction CO | Rantoul | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| CGCrown Gym Mat INC | Barrington | IL | Miscellaneous Manufacturing339920 | — | ◇ UNVERIFIED |
| CBCrownline Boats INC | West Frankfort | IL | Transportation Equipment Manufacturing336612 | — | ◇ UNVERIFIED |
| CCrush-crete | Addison | IL | Nonmetallic Mineral Product Manufacturing327991 | — | ◇ UNVERIFIED |
| CRCts Reeves Frequency Products | Sandwich | IL | Computer and Electronic Product Manufacturing334419 | — | ◇ UNVERIFIED |
| CWCts Wireless Components | Bloomingdale | IL | Computer and Electronic Product Manufacturing334310 | — | ◇ UNVERIFIED |
| CSCuiferi Sawdust Milling | Collinsville | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| CICulligan International CO | Vernon Hills | IL | Beverage and Tobacco Product Manufacturing312112 | — | ◇ UNVERIFIED |
| CUCulligan USA | Northbrook | IL | Machinery Manufacturing333319 | — | ◇ UNVERIFIED |
| CCCurran Contracting CO | Grayslake | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| CCCurran Contracting CO | Crystal Lake | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| CCCurran Contracting CO | Dekalb | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| CRCurry Ready Mix INC | Pawnee | IL | Nonmetallic Mineral Product Manufacturing327320 | — | ◇ UNVERIFIED |
| CRCurry Ready Mix of Carlinville INC | Staunton | IL | Nonmetallic Mineral Product Manufacturing327320 | — | ◇ UNVERIFIED |
| CRCurry Ready Mix of Carlinville INC | Raymond | IL | Nonmetallic Mineral Product Manufacturing327320 | — | ◇ UNVERIFIED |
| CLCurtis Lowe | Lena | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| CTCurtis Thermal Processing | Machesney Park | IL | Fabricated Metal Product Manufacturing332811 | — | ◇ UNVERIFIED |
| CICurwood Incorporated | Murphysboro | IL | Paper Manufacturing322221 | — | ◇ UNVERIFIED |
| CCCustom Compounding Services LLC | Rockford | IL | Chemical Manufacturing325991 | — | ◇ UNVERIFIED |
| CGCustom Graphics INC | Bartonville | IL | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
| CHCustom Hard Chrome | Rosemont | IL | Fabricated Metal Product Manufacturing332813 | — | ◇ UNVERIFIED |
| CPCustom Plastics | Elk Grove Village | IL | Plastics and Rubber Products Manufacturing326121 | — | ◇ UNVERIFIED |
| CSCustom Stainless Steel INC | Benton | IL | Miscellaneous Manufacturing339999 | 1-19 | ◇ UNVERIFIED |
| CTCustom Tapes INC | Harwood Heights | IL | Plastics and Rubber Products Manufacturing326112 | — | ◇ UNVERIFIED |
| DIDahlgrens INC | Oglesby | IL | Wood Product Manufacturing321911 | — | ◇ UNVERIFIED |
| DDDahlstrom Display INC | Broadview | IL | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
| DEDai Environmental INC | Rosemont | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| DHDale H. Knack | Gridley | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| DCDana Companies LLC | Roscoe | IL | Machinery Manufacturing333613 | — | ◇ UNVERIFIED |
| DCDana Companies LLC | Roscoe | IL | Machinery Manufacturing333613 | — | ◇ UNVERIFIED |
| DDDana Driveshaft Manufacturing LLC | Sterling | IL | Machinery Manufacturing333111 | — | ◇ UNVERIFIED |
| DCDanaher Controls | Gurnee | IL | Computer and Electronic Product Manufacturing334513 | — | ◇ UNVERIFIED |
| DBDanville Brass & Aluminum CO | Danville | IL | Primary Metal Manufacturing331524 | — | ◇ UNVERIFIED |
| DSDanville Steel | Danville | IL | Fabricated Metal Product Manufacturing332312 | — | ◇ UNVERIFIED |
| DIDarling Ingredients INC | National Stock Yards | IL | Food Manufacturing311613 | — | ◇ UNVERIFIED |
| DIDasco INC | Rockford | IL | Fabricated Metal Product Manufacturing332216 | — | ◇ UNVERIFIED |
| DSDa Stuart CO | Chicago | IL | Petroleum and Coal Products Manufacturing324191 | — | ◇ UNVERIFIED |
| DADavid A. Andersen | Bondville | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| DSDavid Simmons | Dwight | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| DYDavid Yanders | Rankin | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| DWDavis Welding | Gibson City | IL | Fabricated Metal Product Manufacturing332999 | — | ◇ UNVERIFIED |
| DLDawson Logistics | Tilton | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| DIDay International Chemical Products Div | Addison | IL | Chemical Manufacturing325612 | — | ◇ UNVERIFIED |
| DMDb Metal Finishing LLC | Rockford | IL | Fabricated Metal Product Manufacturing332812 | — | ◇ UNVERIFIED |
| DCD Construction INC | Morris | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| DDDean Dairy Holdings LLC | Huntley | IL | Food Manufacturing311511 | — | ◇ UNVERIFIED |
| DIDean Illinois Dairies, LLC | Harvard | IL | Food Manufacturing311511 | — | ◇ UNVERIFIED |
