| Mairwa | |
| Settlement Type: | City (Nagar Panchayat) |
| Pushpin Map: | India Bihar |
| Pushpin Label Position: | right |
| Pushpin Map Caption: | Location in Bihar, India |
| Coordinates: | 26.23°N 84.15°W |
| Subdivision Type: | Country |
| Subdivision Name: |  India |
| Subdivision Type1: | State |
| Subdivision Name1: | Bihar |
| Subdivision Type2: | District |
| Subdivision Name2: | Siwan |
| Subdivision Type3: | Subdivision |
| Subdivision Name3: | Siwan |
| Subdivision Type4: | Block |
| Subdivision Name4: | Mairwa block |
| Established Title: | Established |
| Government Type: | Nagar Panchayat |
| Governing Body: | Mairwa Nagar Panchayat |
| Unit Pref: | Metric |
| Area Total Km2: | 6.23 |
| Population Total: | 23565 |
| Population As Of: | 2011 |
| Population Density Km2: | auto |
| Demographics Type1: | Languages |
| Demographics1 Title1: | Official |
| Demographics1 Info1: | Bhojpuri, Hindi & English |
| Timezone1: | IST |
| Utc Offset1: | +5:30 |
| Postal Code Type: | Pin Code |
| Registration Plate: | BR-29 |
| Blank Name: | Climate |
| Blank Info: | Cwa |
Mairwa City Council is a nagar panchayat (city council) located in Siwan district of Bihar in India.
The total area of the council is 6.23km2, and its total population is 23,565.[1] The city is divided into 13 wards. It is the block headquarters of Mairwa block. It is famous for the historical temple of Baba Hari Ram Brahma.