| # | Village / Locality | Post Office | PIN Code | Sub District | Type |
|---|---|---|---|---|---|
| 1401 | Siarahi | Gokhula BO | 📍 845451 | Narkatiaganj | Branch Post Office |
| 1402 | Sidhaw | Naraipur SO | 📍 845105 | Bagaha | Post Office - PO |
| 1403 | Sidhaw | Sidhaw BO | 📍 845105 | Sidhaw | Branch Post Office |
| 1404 | Sidhawa | Sidhaw BO | 📍 845105 | Sidhaw | Branch Post Office |
| 1405 | Sigahwa | Taulaha Champaran BO | 📍 845455 | Narkatiaganj | Branch Post Office |
| 1406 | Sigari-Bigri | Ramnagar SO West Champaran | 📍 845106 | Ramnagar | Post Office - PO |
| 1407 | Sigri | Sigari Bigari BO | 📍 845106 | Ramnagar | Branch Post Office |
| 1408 | Sihnaula | Chauhatta BO | 📍 845451 | Mainatanr | Branch Post Office |
| 1409 | Sihpatti | Bagahi BO | 📍 845452 | Jogapatti | Branch Post Office |
| 1410 | Sihpur | Chanpatia R S SO | 📍 845449 | Chanpatia | Post Office - PO |
| 1411 | Sihpur | Sihpur BO | 📍 845449 | Lauriya | Branch Post Office |
| 1412 | Sihpurwa | Jamunia BO | 📍 845455 | Gaunaha | Branch Post Office |
| 1413 | Sikta | Dianmarawa BO | 📍 845103 | Ramnagar | Branch Post Office |
| 1414 | Sikta | Sikta SO | 📍 845307 | Sikta | Post Office - PO |
| 1415 | Sikta | Baswariya BO | 📍 845453 | Lauriya | Branch Post Office |
| 1416 | Sikta Kalan | Barwa Ojha BO | 📍 845452 | Jogapatti | Branch Post Office |
| 1417 | Sikta Khurd | Barwa Ojha BO | 📍 845452 | Jogapatti | Branch Post Office |
| 1418 | Siktanr | Harpur BO | 📍 845101 | Bagaha | Branch Post Office |
| 1419 | Sikti | Khairpokhara BO | 📍 845105 | Bagaha | Branch Post Office |
| 1420 | silautia | Bargo BO | 📍 845103 | Ramnagar | Branch Post Office |
| 1421 | Singahi | Bagahi BO | 📍 845103 | Ramnagar | Branch Post Office |
| 1422 | Singahi | Semari Dumari BO | 📍 845106 | Ramnagar | Branch Post Office |
| 1423 | Singari | Bagaha SO | 📍 845101 | Bagaha | Post Office - PO |
| 1424 | Singari | Singari BO | 📍 845101 | Bagaha | Branch Post Office |
| 1425 | Singari- Garhwa | Singari BO | 📍 845101 | Bagaha | Branch Post Office |
| 1426 | Singasani | Pindari BO | 📍 845306 | Mainatanr | Branch Post Office |
| 1427 | Sirahwa | Serwa Masjidwa BO | 📍 845455 | Narkatiaganj | Branch Post Office |
| 1428 | Sirahwa | Sugauli BO | 📍 845455 | Narkatiaganj | Branch Post Office |
| 1429 | Sirauna | Patilar BO | 📍 845101 | Bagaha | Branch Post Office |
| 1430 | Sirhwa | Rampur BO | 📍 845451 | Mainatanr | Branch Post Office |
| 1431 | Sirinagar | Taulaha BO | 📍 845104 | Thakrahan | Branch Post Office |
| 1432 | Siriswa | Sariswa Bazar BO | 📍 845454 | Majhaulia | Branch Post Office |
| 1433 | Sirji Barhampur | Sirisia BO | 📍 845101 | Sidhaw | Branch Post Office |
| 1434 | Sirkohiya | Mathia Brit BO | 📍 845454 | Majhaulia | Branch Post Office |
| 1435 | Sirsia | Bagaha SO | 📍 845101 | Bagaha | Post Office - PO |
| 1436 | Sirsia | Sirisia BO | 📍 845101 | Bagaha | Branch Post Office |
| 1437 | Sirsia | Chuhari SO | 📍 845450 | Chanpatia | Post Office - PO |
| 1438 | Sirsia | Sirisia BO | 📍 845450 | Chanpatia | Branch Post Office |
| 1439 | Sirsia | Barwa Ojha BO | 📍 845452 | Jogapatti | Branch Post Office |
| 1440 | Sirsia | Serwa Masjidwa BO | 📍 845455 | Gaunaha | Branch Post Office |
| 1441 | Sirsia Mathia | Balua Rampurwa BO | 📍 845438 | Bairia | Branch Post Office |
| 1442 | Sirsiya | Behari Bankatwa BO | 📍 845307 | Sikta | Branch Post Office |
| 1443 | Sisai | Gaunaha SO | 📍 845102 | Gaunaha | Branch Post Office |
| 1444 | Sisai | Madhubani SO | 📍 845104 | Thakrahan | Post Office - PO |
| 1445 | Sisai | Sisai BO | 📍 845104 | Lauriya | Branch Post Office |
| 1446 | Sisai | Maldi BO | 📍 845451 | Narkatiaganj | Branch Post Office |
| 1447 | Sisai Lathihawa | Sisai BO | 📍 845104 | Madhubani | Branch Post Office |
| 1448 | Sisba | Chandraha BO | 📍 845101 | Bagaha | Branch Post Office |
| 1449 | Sisba | Siswa Basantpur BO | 📍 845453 | Bagaha | Branch Post Office |
| 1450 | Siswa | Gudgudi BO | 📍 845106 | Ramnagar | Branch Post Office |