Tiswadi (Portuguese: Ilhas de Goa, lit. 'Islands of Goa', or simply Ilhas) is a sub-district in the district of North Goa, situated in the Indian coastal state of Goa. It is the largest and populous island of Goa situated in the basin of the Zuari and Mandovi rivers. It was one of the first territories to be annexed by Portugal in 1510 AD. Both the state capital Panaji, and the former capital Old Goa are within the sub-district. It is one of 6 major islands between the Mandovi and Zuari rivers.