| Company Name | City | License |
|---|---|---|
| Air Commander Test & Balance LLC | Spokane Valley | |
| AIO LLC | Missoula | |
| Aflame Fire Protection | Helena | |
| Advantage Asphalt | Missoula | |
| Advanced Pump & Equipment, Inc. | Belgrade | |
| Advanced Lawncare & Maintenance LLC | Missoula | |
| Advanced Earthworks- Helena | Helena | |
| ACI Northwest, Inc. | Coeur d'Alene | |
| ACE, Inc | Helena | |
| ACE Solutions, LLC | Post Falls | |
| ABT Controls | Missoula | |
| ABC Seamless | Missoula | |
| Abatement Contractors of Montana | Missoula | |
| AAA Plumbing and Heating | Frenchtown | |
| AAA Construction of Missoula | Missoula | |
| A-Core of Missoula | Missoula | |
| A&E Design | Missoula | |
| 64 Mile Distillery | Anaconda | |
| 4G Plumbing and Heating, Inc | Missoula | |
| 406 Mudworx LLC | Missoula | |
| 3 Rivers Landworks | Clinton | |
| 2M Company | Missoula |