| Business | Phone |
| Calhoun County Administration 315 W Green St, Marshall 49068 | (269) 781-0700 |
| Calhoun County Commissioners 315 W Green St, Marshall 49068 | (269) 781-0910 |
| Calhoun County Dog Control 212 S Grand St, Marshall 49068 | (269) 781-0941 |
| Calhoun County Drain Comm 315 W Green St, Marshall 49068 | (269) 781-0790 |
| Calhoun County Equalization 315 W Green St, Marshall 49068 | (269) 781-0745 |
| Calhoun County Facilities-Svc 315 W Green St, Marshall 49068 | (269) 781-0815 |
| Calhoun County Finance 315 W Green St, Marshall 49068 | (269) 781-0971 |
| Calhoun County Human Resources 315 W Green St, Marshall 49068 | (269) 781-0980 |
| Calhoun County Juvenile Home 14555 18 1/2 Mile Rd, Marshall 49068 | (269) 781-7221 |
| Calhoun County Msu Extension 315 W Green St, Marshall 49068 | (269) 781-0784 |
| Calhoun County Planning Dept 315 W Green St, Marshall 49068 | (269) 781-9841 |
| Calhoun County Purchasing 315 W Green St, Marshall 49068 | (269) 781-0981 |
| Calhoun County Treasurer's Ofc 315 W Green St, Marshall 49068 | (269) 781-0807 |