Jainagar, Bihar
| Jainagar Jaynagar | |
|---|---|
| Town | |
| Railway station in Jainagar | |
| Coordinates: 26°35′33″N 86°08′14″E / 26.59250°N 86.13722°E | |
| Country | India | 
| State | Bihar | 
| District | Madhubani | 
| Population  (2017) | |
|  • Total | 217,820 | 
| Languages | |
| • Official | Maithili, Hindi | 
| Time zone | UTC+5:30 (IST) | 
| PIN | 847226 | 
| Telephone code | 06246 | 
| Lok Sabha constituency | Jhanjharpur | 
| Vidhan Sabha constituency | Khajauli | 
| Website | madhubani | 
Jainagar (also spelled as Jaynagar) is a town and a notified area of Madhubani district in the Indian state of Bihar.