Biasca is a town of the district of Riviera in the canton of Ticino in Switzerland.

Biasca is first mentioned in 830 as Aviasca in the Liber viventium of Pfäfers Abbey . In 1119 it was mentioned as Abiasca.

In 948, the Bishop of Vercelli donated the area around Biasca to the Bishop of Milan . This led to the spiritual and secular domination of the valley north of Bellinzona . During the Bishop's conflicts with the Holy Roman Empire over the Lombardy provinces, Biasca and the surrounding region suffered from armies marching through the valley.