| ACArch Chemicals Specialty Products, INC. | Seward | IL | Chemical Manufacturing325131 | — | ◇ UNVERIFIED |
| ADArcher Daniels-bushnell | Bushnell | IL | Food Manufacturing311224 | — | ◇ UNVERIFIED |
 Archer Daniels Midland CO | Granite City | IL | Food Manufacturing311222 | — | ◇ UNVERIFIED |
| Archer Daniels Midland CO | Decatur | IL | Food Manufacturing311222 | — | ◇ UNVERIFIED |
| Archer Daniels Midland CO | Peoria | IL | Food Manufacturing311213 | — | ◇ UNVERIFIED |
| Archer Daniels Midland CO | Steger | IL | Food Manufacturing311823 | — | ◇ UNVERIFIED |
| ADArcher Daniels Midwest | Decatur | IL | Food Manufacturing311119 | — | ◇ UNVERIFIED |
| ASArcher Screw Products | Franklin Park | IL | Fabricated Metal Product Manufacturing332721 | — | ◇ UNVERIFIED |
| ACArchibald Candy Company | Chicago | IL | Food Manufacturing311330 | — | ◇ UNVERIFIED |
| ASArchitectural Specialty Products INC | Chicago | IL | Fabricated Metal Product Manufacturing332323 | — | ◇ UNVERIFIED |
| AGArdagh Glass INC. (lincoln) | Lincoln | IL | Nonmetallic Mineral Product Manufacturing327213 | — | ◇ UNVERIFIED |
| ADArea Diesel Service INC | Carlinville | IL | Fabricated Metal Product Manufacturing332721 | — | ◇ UNVERIFIED |
| ABArends Bros. LLC. | Melvin | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| ABArgo Biodiesel Plant | Argo | IL | Chemical Manufacturing325998 | — | ◇ UNVERIFIED |
| APArgus Press INC | Niles | IL | Printing and Related Support Activities323110 | — | ◇ UNVERIFIED |
| APArkay Plastics Illinois INC | Paris | IL | Plastics and Rubber Products Manufacturing326121 | — | ◇ UNVERIFIED |
| AIArkema INC | Lemont | IL | Chemical Manufacturing325211 | — | ◇ UNVERIFIED |
| AIArkwright INC | Charleston | IL | Paper Manufacturing322211 | — | ◇ UNVERIFIED |
| ALArlington LLC | Arlington Heights | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| ATArmstrong Tools INC | Chicago | IL | Machinery Manufacturing333515 | — | ◇ UNVERIFIED |
| AGArnold Graphic Resources INC. | Schaumburg | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| ARA & R Plating | Bridgeview | IL | Fabricated Metal Product Manufacturing332813 | — | ◇ UNVERIFIED |
| AIArris International INC | Rock Falls | IL | Computer and Electronic Product Manufacturing334000 | — | ◇ UNVERIFIED |
| AGArrow Group Ind INC | Breese | IL | Fabricated Metal Product Manufacturing332311 | — | ◇ UNVERIFIED |
| APArrow Pattern and Foundry CO | Bridgeview | IL | Primary Metal Manufacturing331528 | — | ◇ UNVERIFIED |
| AArtco | Lemont | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| ATAsian Trendwares INC | Lombard | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| AAsko | South Holland | IL | Machinery Manufacturing333515 | — | ◇ UNVERIFIED |
| AGAspen Graphics Printing CORP | Addison | IL | Printing and Related Support Activities323110 | — | ◇ UNVERIFIED |
| ASAsphalt Sales & Products INC | Staunton | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| ASAsphalt Sales & Products INC | Edwardsville | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| ASAsphalt Sales & Products INC | O'fallon | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| ABAspire Bakeries LLC | Alsip | IL | Food Manufacturing311821 | — | ◇ UNVERIFIED |
| AAAssa Abloy | Carol Stream | IL | Fabricated Metal Product Manufacturing332321 | — | ◇ UNVERIFIED |
| APAssembled Products | Buffalo Grove | IL | Fabricated Metal Product Manufacturing332999 | — | ◇ UNVERIFIED |
| AMAstec Mobile Screens | Sterling | IL | Machinery Manufacturing333120 | — | ◇ UNVERIFIED |
| AIAstroblast INC | Franklin Park | IL | Fabricated Metal Product Manufacturing332813 | — | ◇ UNVERIFIED |
| ATAstro Tire Removal INC | Thomasboro | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| AFAta Finishing CORP | Skokie | IL | Fabricated Metal Product Manufacturing332812 | — | ◇ UNVERIFIED |
| AFAtherton Foundry Products INC | Riverdale | IL | Primary Metal Manufacturing331524 | — | ◇ UNVERIFIED |
| AFAtk Foods INC | Chicago | IL | Food Manufacturing311612 | — | ◇ UNVERIFIED |
| APAtlantic Press INC | Oak Lawn | IL | Printing and Related Support Activities323110 | — | ◇ UNVERIFIED |
| ASAtlas Solid Tooling | Arlington Heights | IL | Fabricated Metal Product Manufacturing332813 | — | ◇ UNVERIFIED |
| ATA to Z Offset Printing & Publishing INC | Skokie | IL | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
| AWAt&t Wireless Navy Pier-water | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| AMAtwood Mobile Products | Rockford | IL | Fabricated Metal Product Manufacturing332510 | — | ◇ UNVERIFIED |
| AMAubrey Manufacturing INC | Union | IL | Fabricated Metal Product Manufacturing332812 | — | ◇ UNVERIFIED |
 Augusta Fiberglass Coatings INC | Newton | IL | Plastics and Rubber Products Manufacturing326199 | — | ◇ UNVERIFIED |
| AFAugusta Fire Protection District | Augusta | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| ABAurora Blacktop INC | Yorkville | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
