| Kaina | |
| Other Name: | Kaina-Mahe Gram Panchayat |
| Settlement Type: | village |
| Pushpin Label Position: | right |
| Pushpin Map Caption: | Location in Bihar, India |
| Subdivision Type: | Country |
| Subdivision Name: |  India |
| Subdivision Type1: | State |
| Subdivision Name1: | Bihar |
| Subdivision Type2: | District |
| Subdivision Name2: | Samastipur |
| Unit Pref: | Metric |
| Population Total: | 4000 |
| Population Density Km2: | auto |
| Demographics Type1: | Languages |
| Demographics1 Title1: | Official |
| Demographics1 Info1: | Maithili, Hindi, English |
| Timezone1: | IST |
| Utc Offset1: | +5:30 |
| Postal Code: | 848209 |
| Registration Plate: | BR- |
| Blank1 Name Sec1: | Coastline |
| Blank1 Info Sec1: | 0km (00miles) |
| Blank2 Name Sec1: | Nearest city |
| Blank2 Info Sec1: | DARBHANGA |
| Blank3 Name Sec1: | Lok Sabha constituency |
| Blank3 Info Sec1: | SAMASTIPUR |
| Blank4 Name Sec1: | Vidhan Sabha constituency |
| Blank4 Info Sec1: | ROSERA |
| Iso Code: | IN-BR |
Kaina is a village in Singhia block in Rosera Subdivision in Samastipur District in the state of Bihar, India. Kaina has 5 localities named Panchkhuttee, Tinkhuttee, Pachwair toal, Tola and Mandal Tol. Its population is around 2331.
Kaina is mostly a village of Brahmins(maithil), 80% of the population have the surname Jha. 4 ponds and 4 temples are situated in the village. Literacy level is almost 80 to 85% in the village.