| Office Name | Siwan H.O |
| Pincodes | 841226 |
| Area | Siwan |
| Office Status | Branch Post Office |
| Postal Circle | Bihar |
| Postal Division | Siwan |
| Postal Region | Muzaffarpur |
| District | Siwan |
| State | Bihar |
| Telephone No. | 06154-242989 |
| Office Name | Siwan S.O |
| Pincodes | 136033 |
| Area | Siwan |
| Office Status | Sub Post Office |
| Postal Circle | Haryana |
| Postal Division | Kurukshetra |
| Postal Region | Ambala Hq |
| District | Kaithal |
| State | Haryana |
| Telephone No. | 01746-240830 |
| Office Name | Siwan B.O |
| Pincodes | 229126 |
| Area | Siwan |
| Office Status | Branch Post Office |
| Postal Circle | Uttar Pradesh |
| Postal Division | Rae Bareilly |
| Postal Region | Lucknow Hq |
| District | Raebareli |
| State | Uttar Pradesh |
| Telephone No. | Na |