Chiasso is a municipality in the district of Mendrisio in the canton of Ticino in Switzerland. As the southernmost of Switzerland's municipalities, Chiasso is on the border with Italy, in front of Ponte Chiasso. The municipality of Chiasso includes the villages of Boffalora, Pedrinate and Seseglio. In 2007, the three mayors of Chiasso, Vacallo and Morbio Inferiore decided to unite into one commune.