Jainagar (also spelled as Jaynagar) is a town and a notified area of Madhubani district in the Indian state of Bihar.
As of the 2011 India census, Jainagar had a total population of 21,782. Males constituted 51% of the population and females 49%. Jainagar had an average literacy rate of 79%, higher than the national average of 74.04%. Male literacy was 86%, and female literacy was 71%. 16% of the population were under 60 years of age.[1]