| # | Company name | Role | # of projects |
|---|---|---|---|
| 21 | Cagley Harman & Leisk | Structural engineering | 0 |
| 22 | Cailor & Associates, LLC | Structural engineering | 2 |
| 23 | Calabrese & Kuncas | Structural engineering | 0 |
| 24 | Calder-Kankainen Consulting Engineers | Structural engineering | 0 |
| 25 | Call Engineering | Structural engineering | 0 |
| 26 | Callahan Engineering | Structural engineering | 0 |
| 27 | Callarman Associates Inc | Structural engineering | 1 |
| 28 | Calsae Inc. | Structural engineering | 1 |
| 29 | Campbell & Associates Consulting Engineers, Inc. | Structural engineering | 43 |
| 30 | Campbell & Assocs Consulting Engineers | Structural engineering | 1 |
| 31 | Campbell Comeau Engineering | Structural engineering | 1 |
| 32 | Cankat-essman Inc. | Structural engineering | 4 |
| 33 | Cantilever Design, LLC | Structural engineering | 2 |
| 34 | Capano & Parker Eng. | Structural engineering | 0 |
| 35 | Cape Design Engr Co | Structural engineering | 2 |
| 36 | Capes Engineering | Structural engineering | 1 |
| 37 | Capri Engineering | Structural engineering | 0 |
| 38 | Cardno | Structural engineering | 3 |
| 39 | Cardno Haynes Whaley, Inc. | Structural engineering | 145 |
| 40 | Cardno Haynes Whaley, Inc. | Structural engineering | 17 |