Kaina is a village in Singhia block in Samastipur district in the state of Bihar, India. Kaina has 5 localities named Panchkhuttee, Tinkhuttee, Pachwair toal, Tola par and Puwari Tol. Its population is around 2331.It has around 508 households.
Kaina is a village of Brahmins(maithil), 99% of the population have the surname Jha.4 ponds and 4 temples are situated in the village. Litracy level is also good in the village . Bishambar Choudhry, son of Digambar Choudhry from PanchKhutti tol, has topped SSC exam in 2012 and is now a Custom Officer in Kolkata.