The list is the FIPS codes of Connecticut counties. All the FIPS codes are starting with 09.
| County | FIPS Code |
| Fairfield | 09001 |
| Hartford | 09003 |
| Litchfield | 09005 |
| Middlesex | 09007 |
| New Haven | 09009 |
| New London | 09011 |
| Tolland | 09013 |
| Windham | 09015 |
All codes are cited from United States Department of Agriculture [28].