- The Dahanu fort has been once described as The fort, on the north bank of the river at a little distance from its mouth, is of cut-stones and well built. In 1818 the walls, which averaged 38 feet high and 10 feet thick, were in excellent condition, defended by four casemated towers with ruined terraces.
- Dahanus historical significance can be traced back to 16th century AD. When the Portuguese had firmly established their dominion on the west coast of India between Daman in North and Karanja in the South, they divided their Thana territories into two divisions viz. Daman and Vasai (also known as Basai by Muslims, Bacaim by Portuguese, Bajipur by Marathas and Bassein by the British), then an important ship building center whereupon Dahanu (then called Danu) was included in the Daman division along with three other districts -- Sanjan, Tarapur and Mahim.1