Dehri was one of the biggest Industrial hubs in Bihar.
The Rohtas Industries Limited industrial complex at Dalmianager, Rohtas District, Bihar State, was established by Ramkrishna Dalmia from the early 1930's. A sugar factory was the first to open in 1933, followed by a Cement Works in 1937; a Paper Factory in 1938, an Asbestos Factory in 1944 and a Soap Factory in 1964. The industrial site was next to the 2 ft 6in/762mm narrow gauge(NG)Dehri-Rohtas Light Railway(DRLR) station of Rohtas and the locomotives that worked at this site appear to have been owned by DRLR and operated by them for Rohtas Industries Ltd. The extent of the NG lines within the site has not been established. The East Indian Railway(EIR) 'Grand Chord' broad gauge(BG) line between Gaya and Moghal Sarai passed by the site. There was a branch from the industrial site to the EIR, however the extent of the BG lines within the site has not been established. The site closed for a time in the 1980's and went into liquidation in 1995.