| Business | Phone |
| Applied Technologies 900 Commerce Dr, Oak Brook 60523 | (630) 468-5077 |
| Hanson Professional Svc Inc 815 Commerce Dr 200, Oak Brook 60523 | (630) 990-3800 |
| Hosler & Hosler 820 Merry Ln, Oak Brook 60523 | (630) 573-0500 |
| Mactec 1200 Jorie Blvd 230, Oak Brook 60523 | (630) 571-2162 |
| Meyer Design Group Inc 16 Olympia Ct, Oak Brook 60523 | (630) 230-0446 |
| Narsan Corp 6 Royal Vale Dr, Oak Brook 60523 | (630) 850-9800 |
| P & D Consultants Inc 1420 Kensington Rd 100, Oak Brook 60523 | (630) 990-8788 |
| Parsons Engineering Science 1000 Jorie Blvd, Oak Brook 60523 | (630) 990-7200 |
| Syd & Assoc 1100 Jorie Blvd 151, Oak Brook 60523 | (630) 571-0720 |
| Varley-Campbell & Assoc Inc 2625 Butterfield Rd 138s, Oak Brook 60523 | (630) 573-7730 |
| Zimmer Consultants Inc 125 Windsor Dr 109, Oak Brook 60523 | (630) 571-0050 |