Tiswadi, formerly known as Ilhas, is a taluka in the district of North Goa, situated in the Indian coastal state of Goa. It is an estuarine island situated on the confluence of the Mandovi and Zuari rivers. It was one of the first territories to be annexed by the Portuguese in the 16th century. Both the state capital Panaji, and the erstwhile capital Old Goa lie within the sub-district. It is the biggest and the most populated of the six major islands between the Mandovi and Zuari rivers.