On the banks of the Son River, Dehri is one of the significant towns in the Rohtas district of Bihar. It is located on National Highway 2 (NH 2) about 45 km. from Rohtasgarh Fort. This city has good road communication and is situated on the Delhi-Kolkata rail route. It is located at a height of 99 metres (324feet) above mean sea level. It is located between 24.87° North latitude and 84.18° East longitude.

The main occupation of the people living here is agriculture and therefore Dehri produces huge quantities of rice. Sugar production; saw milling and ghee processing are among the prominent industries. A hydroelectric dam is present here and the best time to visit the place is in October.

According to the 2001 census report, Dehri had a population of 119,007 inhabitants. Males constitute 53% of the population and females 47% .In Dehri, 15% of the population is less than six years of age. Dehri has an average literacy rate of 66%, which is higher than the national average literacy rate, which is 59.5%. The male literacy rate is 74% and the female literacy rate is 57%.