| Business | Phone |
| Apogen Technologies 4031 University Dr # 400, Fairfax 22030 | (703) 434-4000 |
| Applied Engineering Management 11781 Lee Jackson Memorial Hwy, Fairfax 22033 | (703) 273-4486 |
| Argon Engineering 12701 Fair Lakes Cir, Fairfax 22033 | (703) 815-0365 |
| Charter Engineering Cnsltnts 10560 Main St, Fairfax 22030 | (703) 359-8450 |
| Creative Engineering Concepts 3545 Chain Bridge Rd, Fairfax 22030 | (703) 359-5959 |
| Dade Moller & Assoc 11096 Lee Hwy, Fairfax 22030 | (703) 273-6750 |
| A J Winkler 5424 Southport Ln, Fairfax 22032 | (703) 992-0649 |
| Ellis Engineering 2931 Eskridge Rd # D200, Fairfax 22031 | (703) 573-3700 |
| Gannett Fleming Inc 4401 Fair Lakes Ct # 100, Fairfax 22033 | (703) 273-5028 |
| Goe Env Engineers 10875 Main St, Fairfax 22030 | (703) 591-7170 |
| Metro Construction Engineer Co 10560 Main St, Fairfax 22030 | (703) 385-4029 |
| Tecolote Research 11350 Random Hills Rd 800, Fairfax 22030 | (703) 934-6089 |
| W P Cioffi Engineering 2929 Eskridge Rd, Fairfax 22031 | (703) 992-7748 |
| West Oaks Iii 3702 Pender Dr 103, Fairfax 22030 | (703) 273-7831 |
| Weston Engineering 3975 University Dr, Fairfax 22030 | (703) 691-7540 |
| Williams Fairey Engineering 5012 Sideburn Rd, Fairfax 22032 | (703) 323-6112 |
| Prime Inc 4009 Williamsburg Ct, Fairfax 22032 | (703) 278-9000 |