According to legends, Rohita, son of King Harischandra, realizing the anger to his life, stayed here several years in exile. The fort is named after this prince. It was also known as Quila Rohtas. It was the shelter for the Mughal family in times of war. Military operations were undertaken from here. According to the existing records, there were 84 passages to the hill with 14 having gates, 10 of these were closed by Sher Shah Suri. Today the fort is a part of a plateau, it is 45 km and 39 km from Dehri on Sone and Sasaram respectively.
A hill station on the Kaimur hill and situated at 1490 feet . It is 4 miles across east to west and 5 miles north to south, and 28 miles in circumference. There are several villages now on the plateau and cultivation. There are springs of water, and also wells which are sweet water.
The fort is sprawled across the hill with ramparts growing from the cliff. The gates and bastions are massive and devoid of embellishments but the ashlar is finely joined. It seems to still hold together the fallen rocks. Throughout the Suri period the Rohtasgarh fort was guarded by a strong garrison of 10,000 matchlock men .
Akbar acquired the fort in 1587 and gave it to Raja Maan Singh, who was appointed the Governor of Bihar. Rohtas was the provincial capital of Maan Singh till 1607. In 1621, Prince Khurram sought refuge here. Khurram's younger son, Murad was born here to his wife Arjamand Bano (Mumtaz Mahal). When Khurram became emperor Shah Jehan, he placed the fort under the command of Ikhlas Khan and during the reign of Aurangzeb. Rohtasgarh fort as prison was exclusively used for the nobles and princes of royal blood who were condemned to life imprisonment from where very few returned home.
Following the battle of Udhwanala in 1763, Mir Qasim, the Nawab of Bengal was defeated by the East India Company and took shelter here. A year later he lost the battle of Buxar and had to leave the fort. The British finally occupied the fort and Captain Goddard remained here for two months and he destroyed all the military stores. This fort was then abandoned; even today few go there to visit. It is a masterpiece of Pathan architecture.