Padmadurg, also known as Kasa fort, is one of five historical sea forts built by Shivaji Maharaj in 1672-1673 C.E. and located in Raigad District Maharashtra, India. It was built by Marathas to challenge another seaport Janjira which was controlled by Siddis. Padmadurg is one of the sea forts built by Maratha Kings in 1676 in order to control the activities in Arabian sea.It is located in the northwest direction of the Janjira fort at a distance of about 10 km.[1] During cleanup activities in 2012, ASI authorities found around 250 cannonballs of historical value. The sea fort of Padmadurg is not as big as Janjira but still the fort can be visited and enjoyed. Visiting the fort requires taking permission from the Customs/Navy. The fort was not only a part of Sindhudurg's defenses but was also Shivaji Maharaj's main ship construction yard. This fort can also be viewed from Janjira. There was a belt of land from Dandi seashore to Padmadurga but it got blown away under the water in 2004. This fort can be accessed by boats. Boats are mainly available from Murud-Koliwada.