This fort was built by Raja Rai Singhji, the sixth ruler of Bikaner, who ruled form 1571 to 1612 AD. Raja Rai Singhji could Marshal the revenues of a Kingdom increased by the conquest of half Marwar and grant of half Gujrat and made use of ample funds from Jodhpur and Western Deccan for the construction of this fort. A contemporary of Mughal Emperor Akbar and Emperor Jehangir, he held a very high rank in the Imperial court. As a reward for this services as military commander, he was granted fields of Gujrat and Burhanpur by the Emperor. During his tenure in imperial service he traveled far and wide which gave him vision and great ideas about art and architecture and we can see how meticulously these ideas were incorporated in the architectural styles of his building in Junagarh fort.

    The old palaces of Junagarh fort start from Suraj Parol the passage to the old palaces leads through TRIPOLIA, a first reception court. In the past, the palaces guards were accommodated here. Tripolia was got built by Maharaja Dungar Singhji. It is a huge three way structure resting on gigantic stone arches. On entering Tripolia, on the right side, the stairs of VIKRAM VILAS (VIKRAM was the sanskrit name of Rao Bika) durbar hall can be seen which are beautifully carved out of red sand stones from Bikaner. Next comes a ramp that leads to HARMANDIR CHOWK or ZORAWAR MAHAL courtyard and an array of courtyard after courtyard with palace rooms and hall starts, displaying intricate work of art. It is the result of building activity of 16 rules who ruled Bikaner from here for 325 years. The residence of royal family was shifted to Lallgarh Palace when Laxmi Niwas was completed in 1902 A.D.

The important portions of the old palaces in a sequence of visit are Harmandir, Tetis Crore Devi-Devtaon-Ka-Mandir (in this tepmple nearly 700 precious Bronze idols are stored that were brought by the tenth rules Maharaja Anup Singhji from Deccan), Mina Deodhi, Karan Mahal and its Courtyard , Kunwar Pada Mahal, Anup Mahal Courtyard, Phool Mahal ki Sal, Chander Mahal, Rai Niwas Katchery, Anup Mahal, Sardar Niwas (Badal Mahal), Sur Mandir Chaubara, Gaj Mandir Courtyard, Gaj Mandir, Chattar Niwas, Dungar Niwas,  Lal Niwas, Ganga Niwas Mahal and Ganga Niwas Durbar Hall, MAharaja Ganga Sinhgji's study room and Vikram Vilas Durbar hall.