The fort can be approached via a chillingly steep climb. The steps leading up to the fort were cut into the rock of the hill. There are no safety rails on the edge and no ropes on the wall to grab on to. The hardest part is the descent, especially if you have vertigo.
According to legend the fort was built for a queen named Kalavantin but that really seems to be all that anybody knows. Around 1458 Malik Ahmad, the prime minister of the kingdom of Ahmednagar, took over the fort during his conquest of Konkan. The Mughals took control of Prabalgad along with Kalyan, Mahuli, Karnala and a number of other forts after Sambhaji's death.
The fort was conquered by Shivaji from the Mughals in 1657, after he establishing himself in the Kalyan-Bhivandi area. At the time of the attack the fort was governed by Kesar Singh, a Mughal sardar, and was the only fort to put up a strong resistance. On seeing the signs of defeat the women in the fort performed Jauhar, a tradition of self immolation to ensure an honorable and respectful death. Singh died during the battle in October 1657, Shivaji in an act of kindness allowed Singh's mother and her grandchild a safe passage out.