Underi is a fortified island near the mouth of Mumbai harbor south of Prong's Lighthouse. It is a companion fort to Khanderi and currently lies in Raigad district, Maharashtra. The fort has a vast historical episode where the fort was fortified by the Siddi which was later occupied by the Marathas and at last the fort was reigned by the British Government.
Recently Underi became a news sensation when it was sold on May 16, 2006 by State government to Ramesh Kundanmal of Dolphin Stone Crest Estate Pvt Ltd at Rs 2 crore. Later, due to media pressure and consistent protest from trekking community, the deed was cancelled.
The forts still stand in the Arabian Sea as they stood against the British and the Siddi in 17th century, and their walls are still intact. One can see the iron canons with cart wheels on Khanderi, which are rarely found in Maharashtra.