Post Offices List in Sunnyside City, Washington:
| Sunnyside Carrier Annex Post Office | 770 Custer Ave, Sunnyside, WA 98944 |
| Sunnyside Post Office | 713 E Edison Ave, Sunnyside, WA 98944 |
| Sunnyside Carrier Annex Post Office | 770 Custer Ave, Sunnyside, WA 98944 |
| Sunnyside Post Office | 713 E Edison Ave, Sunnyside, WA 98944 |