| Business | Phone |
| Tech 12 11130 Main St, Fairfax 22030 | (703) 891-2771 |
| Advance Engineers Ltd 9900 Main St 502, Fairfax 22031 | (703) 451-5222 |
| Gannett Fleming Inc 4401 Fair Lakes Ct 100, Fairfax 22033 | (703) 222-3704 |
| Gage Babcock & Assoc 11200 Waples Mill Rd 200, Fairfax 22030 | (703) 263-7110 |
| Gale Associates Inc 11781 Lee Jackson Memorial Hwy, Fairfax 22033 | (703) 383-0815 |
| Enersol Technologies Inc 2722 Merrilee Dr 310, Fairfax 22031 | (703) 560-7377 |
| Ogden Energy Group 3211 Jermantown Rd, Fairfax 22030 | (703) 246-0500 |
| Siber Systems 11781 Lee Jackson Memorial Hwy, Fairfax 22033 | (703) 218-1851 |
| Tetra Tech 10306 Eaton Pl, Fairfax 22030 | (703) 278-8447 |
| Applied Engineering Statistics 4400 University Dr, Fairfax 22030 | (703) 993-3645 |
| A Step In Time Structural Fairfax 22030 | (703) 563-9220 |