Collagna is a frazione of the comune (municipality) of Ventasso in the Province of Reggio Emilia in the Italian region Emilia-Romagna, located about 90 kilometres (56 mi) west of Bologna and about 50 kilometres (31 mi) southwest of Reggio Emilia. It was a separate comune until 1 January 2016. Collagna borders the following municipalities: Busana, Comano, Fivizzano, Ligonchio, Ramiseto, Sillano.