Post Offices List in Cavalier County, North Dakota:
| Langdon Post Office | 323 8th Ave, Langdon, ND 58249 |
| Munich Post Office | 410 Main St, Munich, ND 58352 |
| Osnabrock Post Office | 326 Broadway, Osnabrock, ND 58269 |
| Sarles Post Office | 301 Main St, Sarles, ND 58372 |