Dehri is the 136th largest Hindi speaking city of India with a total population of 1,37,231. Dehri is a city in the Rohtas district of Bihar and the highest employment in Rohtas district is in Agriculture, Minerals, Wooden furniture, Readymade Garments and other household industries. The district has 67% of the workforce employed in the Agricultural Sector, 27% in the Industrial Sector and the remaining 6% are Household workers. The important river for Dehri is the Sone river. The major field crops are Rice, Wheat, Maize, Mustard, Pigeon Pea, Pulses, Oilseeds, Mango, Guava, Banana, Lemon, Potato, Onion, Tomato etc. The Longest Railway bridge in India lengths 3.065 km over Sone River which links Sone Nagar and Dehri popularly known as Sone Bridge. Dehri has a very rich heritage. The very famous Sundial Clock (Dhup Ghadi) made in 1871 is situated near the sone river. A sundial is a device that tells the time of day by the apparent position of the Sun in the sky. It was made by irrigation and water resource department of Dehri.