The well-preserved historical centre is situated at 342 m above sea level; over the years, the town has developed lengthwise on a sandstone ridge along which the main road runs. From this main road, many smaller, narrower streets descend towards the medieval walls. Treia was founded in the Middle Ages and was called Montecchio. The name “Treia”, given in 1791, derives from the word “Trea”, the name of a roman settlement that was situated lower than the current village, nearby the church of Santissimo Crocifisso, and was destroyed in a barbarian raid.