Post Offices List in Mount Vernon City, Illinois:
| Mount Vernon Post Office | 301 S 10th St, Mount Vernon, IL 62864 |
| Mount Vernon Carrier Annex Post Office | 1301 Broadway St, Mount Vernon, IL 62864 |
| Mount Vernon Post Office | 301 S 10th St, Mount Vernon, IL 62864 |
| Mount Vernon Carrier Annex Post Office | 1301 Broadway St, Mount Vernon, IL 62864 |