Crosa, Piedmont  Crosa is a "frazione" of the "comune" of Lessona, in the Province of Biella in the Italian region Piedmont, located about northeast of Turin and about northeast of Biella. As of 31 December 2004, it had a population of 332 and an area of . From 1 January 2016 Crosa was absorbed by the neighbouring municipality of Lessona. As an autonomous comune Crosa bordered the following municipalities: Casapinta, Cossato, Lessona, Strona.