| Areraj (Kashi of Bihar) | |
| Nickname: | City of mahakal |
| Settlement Type: | Town |
| Pushpin Map: | India Bihar |
| Pushpin Map Caption: | Location in Bihar, India |
| Coordinates: | 26.5503°N 84.6801°W |
| Subdivision Type: | Country |
| Subdivision Name: |  India |
| Subdivision Type1: | State |
| Subdivision Name1: | Bihar |
| Subdivision Type2: | District |
| Subdivision Name2: | Purvi Champaran |
| Government Type: | Nagar Panchayat |
| Governing Body: | Nagar Panchayat areraj |
| Unit Pref: | Metric |
| Population Total: | 26,014 |
| Population As Of: | 2011 |
| Population Density Km2: | auto |
| Population Demonym: | Arerajbasi |
| Demographics Type1: | Languages |
| Demographics1 Title1: | Official |
| Demographics1 Info1: | Bhojpuri - Hindi |
| Timezone1: | IST |
| Utc Offset1: | +5:30 |
| Area Code Type: | Telephone code |
| Area Code: | 91 6258 |
| Blank1 Name Sec1: | Lok Sabha constituency |
| Blank1 Info Sec1: | Purvi Champaran |
| Blank2 Name Sec1: | Vidhan Sabha constituency |
| Blank2 Info Sec1: | Govindganj |
Areraj is a town and a notified area in East Champaran district in the state of Bihar, India.District entry point Mehsi City
Areraj is located at .
It is just 30 km away from Motihari. No train route is available to reach here, So to reach here one has to go by roadways only. Bus frequency is very good as after every 25minutes(approximately). Its takes around 30–35 minutes to reach Areraj. Areraj is an educational hub in East Champaran. We can say a mini BHU due to many educational institutions resided in single campus.
It is a spiritual city. It's a famous religious place like Jalpa Bhawani, Mansa Mata, Gaytri temple, Bhairav Mandir, Govindganj Ghat and most important "Someshwar Nath" temple is here, which is very very famous temple. In the month of Shravan (August), lot of Shiva's devotee come to visit this place & for whole month Officials have to make arrangements for the people as there is lot of rush during this auspicious month.
Rush increases even more on Monday and Friday, as these days are considered sacred day by Shiva's devotees. People believe that on these two days especially & in month of August particularly, whatever people wish to God is full filled.
Visiting places include 'Ashoka stambha', Lauria and 'Sri Someshwar Nath Mahadev Temple' etc.
India census,[1] Areraj had a population of 26,014 with males constituting 52% of the population and females 48%. Areraj has an average literacy rate of 45%, lower than the national average of 59.5%; with 64% of males and 36% of females literate. 20% of the population is under 6 years of age. Areraj is going to connect on Indian Railway MAP through Hajipur-Sagauli proposed rail line.
Climate is characterised by high temperatures and evenly distributed precipitation throughout the year. The Köppen Climate Classification sub-type for this climate is "Cfa" (Humid Subtropical Climate).