| Business | Phone |
| Anvil Corp 235 Moore Ln # 120, Billings 59101 | (406) 245-9258 |
| Atc Assoc Inc 175 N 27th St # 903, Billings 59101 | (406) 259-1033 |
| Calico Consulting Inc 3318 Harlou Dr, Billings 59102 | (406) 655-4515 |
| Tck Assoc 2757 Gregory Dr N, Billings 59102 | (406) 656-8460 |
| Terracon Consultants Inc 2110 Overland Ave # 124, Billings 59102 | (406) 656-3072 |
| Con'Eer Engineering Inc 1629 Avenue D # C7, Billings 59102 | (406) 252-3237 |
| Sig Ross Engineering 1650 Avenue D # 6, Billings 59102 | (406) 248-4052 |
| Skyline Consulting 4004 Pine Cove Rd, Billings 59106 | (406) 690-1107 |
| Rimrock Engineering Inc 350 S Billings Blvd # 4a, Billings 59101 | (406) 294-8400 |
| Norman Mills Assoc 2930 Grand Ave, Billings 59102 | (406) 656-8024 |
| Hkm Engineering Inc 222 N 32nd St # 700, Billings 59101 | (406) 656-6399 |
| Houston Engineering 1414 Valley Heights Rd, Billings 59105 | (406) 254-1013 |
| Hydrometrics 5602 Hesper Rd, Billings 59106 | (406) 656-1172 |
| Interstate Engineering Inc 1505 Avenue D # 210, Billings 59102 | (406) 256-1920 |
| Marvin & Assoc 1300 N Transtech Way, Billings 59102 | (406) 655-4550 |
| Kadrmas Lee & Jackson 2611 Gabel Rd, Billings 59102 | (406) 245-5499 |
| A T Kersich Pe 2744 Gregory Dr N, Billings 59102 | (406) 655-7883 |
| L A Olson & Assoc Inc 2526 Grand Ave, Billings 59102 | (406) 656-2244 |