- Advanced Electrocircuits Corp
- Affordable Electric
- Al & Ska Dry Cleaners
- All American Transmission Co
- All Around Best Entertainment
- All Safe & Lock Co
- All Welding Equipment Repair
- Allegheny Amusement Co
- Allegheny Brokerage Co
- Allegheny Cooking Equipment
- Allegheny Country Rifle Club
- Allegheny County Dist Justice
- Allegheny Intermediate Unit
- Allegheny Technology Group
