Tatvan is a city on the western shore of Lake Van, in Bitlis Province in eastern Turkey. It is the seat of Tatvan District. Its population is 79,21…Tatvan is a city on the western shore of Lake Van, in Bitlis Province in eastern Turkey. It is the seat of Tatvan District. Its population is 79,214, making it the most populated municipality of the province. The current mayor is Mümin Erol.