| Company | Estimated Employees | ||
| 1 | Cincinnati Financial Corp. | 2900 | |
| 2 | Liberty Mutual | 1300 | |
| 3 | Mercy Hospital Fairfield | 1200 | |
| 4 | Fairfield City School District | 950 | |
| 5 | Medco Health Solutions | 650 | |
| 6 | Koch Foods | 600 | |
| 7 | Tri-County Extended Care | 500 | |
| 8 | Pacific Industries | 425 | |
| 9 | Takumi Stamping | 300 | |
| 10 | City of Fairfield | 275 | |