Prabal Fort (Khalapur Peta; 18°55′ N, 73° 10′ E) on the flat-topped hill of the same name, about eight miles east of Panvel and four west of Matheran, stands about 2,325 feet above sea level. It is believed that Sivaji found substantial treasure on the fort when he captured the fort from the Moghals. The ruined fortifications once included eleven towers and two gateways. In 1818 the gates had long been destroyed, and the works were everywhere falling, the walls of three or four buildings being all that remained. During the rainy months much of the hill was under tillage, the people and their cattle living in the ruins. On the top of the hill was a large pond.
In 1828, a band of Ramosis, who at that time infested the country round Purandhar hill in Poona, came into the Konkan, 300 strong with tents and horses. They met at Prabal, and distributed the following proclamations along with bundles of straw and pieces of charcoal and fuel-
‘Know all men that we Rajesri Umaji Naik and Bhurjaji Naik from our camp at the fort of Purandhar, do hereby give notice, in the year Sursann Surna Ashrin Mayavatain Va alaf 1827, to all Patils, Mahars and others of the villages within the jurisdiction of Ratnagiri in the Southern Konkan and Salsette in the Northern Konkan, that they are not to pay any portion of the revenues arising from their villages to the British Government, and that any instance of disobedience to this mandate shall be punished by fire and sword. All revenues are to be paid to us. This proclamation is sent to you that you may make and keep by you a copy of the same, according to which you are desired to act without any demurring, on pain of having your village razed to the ground. Given under our hand this 25th December 1827.’
In 1862, the fort was reported to be well designed but in ruins. The water-supply was good, but the pond was out of repair and nearly useless. Food supplies were not procurable within eleven miles. In 1881, the hill top which was surrounded by a ruined wall had three ten-feet square cisterns, two on the east and one On the west. Of the fortifications six stone and mortar towers remained with room for five men in each.
From Matheran a footpath leads from Fleetwood bungalow on Cauk Point, across the valley that separates the two hills about four miles to the village of Varosa, and from Varosa about five miles more to the top of Prabal. From Panvel the path leads to the village of Lonavale four miles from the top of the hill [ Dr. Day, Superintendent of Matheran, 31st March 1881.]. The hill-top is about four miles from north to south and three from east to west.