Costa lies on a high slope above theValle Imagna. The village has panoramic views of theBergamo Alps, includingMonte Resegone to the north. From the former ski resort of Forcella Alta and the Pertüs pass, elevation 1,186 to 1,193 metres (3,891 to 3,914 ft), the whole of theBrianza range is visible. For communication reasons the town has had closer links to the San Martino valley,Almenno San Salvatore and the plain, rather than to the rest of the Valle Imagna.
Originally the area seems to have been used forsummer grazing, Costa seems to have been populated year-round only since 1300. The town faces northeast and gets very cold in winter; as a result Costa was known in local slang as "Valle Imagna's warehouse of snow" (la nevera della Valle imagna).
When theRepublic of Venice annexed the province of Bergamo in 1428, the town found itself on the borders between Venice and theDuchy of Milan. This is reflected in the slang of the town, which refers to "foreigners" asbir, the equivalent ofsbirri, a medieval police force. It has been suggested that this dates back to customs officials sent fromVenice to patrol the borders of the republic.
In theCounter-Reformation, a bishop sent a dispatch deploring the state of the village's church that was a result of the poverty of the area. Aplague pit is evidence of the 1630 epidemic described byAlessandro Manzoni.
Since the early 20th century, Costa Valle Imagna has grown in its role of summer resort.