Prior to independence, the Valmiki forests were owned by two erstwhile Zamindari Estates - Bettiah Raj and Ramnagar Raj. The forests were managed for timber production. The state government took over the management of Ramnagar Raj forests in 1950 and the Bettiah Raj forests in 1953 and 1954 under the Bihar Private Protected Forests Act (1947). Subsequently these forests got the status of "Protected Forest" by notification vide no C/PF-6036/52-87 R dated 6th January 1953 covering 909.86 sq.km. Out of these 909.86 sq. km., 8.73 sq. km. of Udaipur forest is far away from main forest of Valmiki and later declared as "Udaipur Wildlife Sanctuary". From early sixties to 1974, the forests were under the management of the State Forest Department. The area was subjected to large scale afforestation with teak, semal, shisham and bamboo. Subsequently, in 1974, the entire forests were handed over to the Bihar State Forest Development Corporation on lease, which managed the forests with commercial objectives.
A fraction of the forest recognized as significant wildlife habitat was notified as "Valmiki Wildlife Sanctuary" vide notification no S.O. wildlife-12/78-2336, dated 4th May 1978 covering area of 462 sq. km. Later in year 1990 an area of 419 sq. km was declared as part of "Valmiki Wildlife Sanctuary" vide no S.O. 136 dated 6th March 1990 covering an aggregate area of 880.78 sq. km."Valmiki National Park" was notified out of the sanctuary vide notification no. S.O. 989 dated 5th December 1990 covering an area of 335.64 sq. km.
The forests were taken back from the State Forest Development Corporation in 1994 and Valmiki Tiger Reserve was constituted as 18th reserve under Project Tiger of Government of India, vide notification no. Vanyaprani 11/94-303-E/Va.Pa. dated 11th March 1994. Total area of Valmiki Tiger Reserve is 898.937 sq. km of which core comprises of 589.789 sq. km & buffer of 309.143 sq. km.