Castel Focognano is comune in the province of Arezzo, Tuscany, central Italy.

The comune lies in the Casentino valley on the left bank of the River Arno.

Although it is named after a village on the slopes of the Alpe di Catenaia, the municipal seat is in the industrial town of Rassina.

During World War II Rassina was home for many American soldiers who were hiding or preparing the offensive on the German army.

Today Rassina is expanding and is becoming one of Casentino's leading industrial centres.