| Office Name | Karsar B.O |
| Pincodes | 841504 |
| Area | Karsar |
| Office Status | Branch Post Office |
| Postal Circle | Bihar |
| Postal Division | Siwan |
| Postal Region | Muzaffarpur |
| District | Siwan |
| State | Bihar |
| Telephone No. | Na |
| Office Name | Karsar B.O |
| Pincodes | 802129 |
| Area | Karsar |
| Office Status | Branch Post Office |
| Postal Circle | Bihar |
| Postal Division | Bhojpur |
| Postal Region | Patna Hq |
| District | Buxar |
| State | Bihar |
| Telephone No. | Na |