Post Offices List in Ottawa City, Illinois:
| Ottawa Post Office | 750 E Etna Rd, Ottawa, IL 61350 |
| Downtown Ottawa Post Office | 405 W Main St, Ottawa, IL 61350 |
| Ottawa Post Office | 750 E Etna Rd, Ottawa, IL 61350 |
| Downtown Ottawa Post Office | 405 W Main St, Ottawa, IL 61350 |