ServiceDepartmentTelephone
| Maintenance/Facilities | County Departments | 517-437-4183 |
| Technology | County Departments | 517-437-3158 |
| Clerk's Office | County Government | 517-437-3391 |
| Commissioner - District 1 | County Government | 517-437-7758 |
| Commissioner - District 2 | County Government | 517-437-7758 |
| Commissioner - District 3 | County Government | 517-437-7758 |
| Commissioner - District 4 | County Government | 517-437-7758 |
| Commissioner - District 5 | County Government | 517-437-7758 |
| Drain Commission | County Government | 517-437-4181 |
| Equalization/Land Information/GIS | County Government | 517-439-9166 |
| Inspection/Permits | County Government | 517-437-4130 |
| Register of Deeds | County Government | 517-437-2231 |
| Treasurer's Office | County Government | 517-437-4700 |
| 9-1-1 Central Dispatch | County Services/Agencies | 517-523-9911 |
| Veteran's Affairs | County Services/Agencies | 517-437-3630 |
| Emergency Management | County Services/Agencies | 517-437-7384 |
| Hillsdale County Fair | County Services/Agencies | 517-437-3622 |
| Medical Examiner | County Services/Agencies | 517-254-4754 |
| Parks Commission | County Services/Agencies | 517-437-4458 |
| Road Commission | County Services/Agencies | 517-437-4458 |
| Circuit Court | Court Services | 517-437-4321 |
| Circuit Court Probation | Court Services | 517-437-3551 |
| District Court | Court Services | 517-437-7329 |
| Drug Court | Court Services | 517-437-7329 |
| Friend of the Court | Court Services | 517-437-4111 |
| Probate Juvenile Court | Court Services | 517-437-4446 |
| Probate Court | Court Services | 517-437-4643 |
| Prosecutor's Office | Court Services | 517-437-1419 |
| Sheriff's Office | Court/Law Enforcement | 517-437-7317 |