| Business | Phone |
| U S Post Office 1802 Morningside Ave, Sioux City 51106 | (712) 277-6408 |
| U S Post Office 214 Jackson St, Sioux City 51101 | (712) 277-6444 |
| U S Post Office 2901 Murphy Dr, Sioux City 51111 | (712) 252-8200 |
| U S Post Office 2617 Pierce St, Sioux City 51104 | (712) 277-6404 |
| U S Post Office 805 Cunningham Dr 138, Sioux City 51106 | (712) 277-6407 |