Post Offices List in Osceola County, Iowa:
| Ashton Post Office | 152 1st Ave, Ashton, IA 51232 |
| Harris Post Office | 312 Main St N, Harris, IA 51345 |
| Melvin Post Office | 246 Main St, Melvin, IA 51350 |
| Sibley Post Office | 412 9th St, Sibley, IA 51249 |
| Ocheyedan Post Office | 851 Main St, Ocheyedan, IA 51354 |