Gerosa was a comune (municipality) in the Province of Bergamo in the Italian region of Lombardy, located about northeast of Milan and about northwest of Bergamo. As of 31 December 2004, it had a population of 381 and an area of .
Gerosa bordered the following municipalities: Blello, Brembilla, Corna Imagna, Fuipiano Valle Imagna, San Giovanni Bianco, San Pellegrino Terme, Taleggio. In 2014 the municipality of Gerosa was merged with Brembilla and the new municipality is named Val Brembilla.