Under the palm and chestnut trees Castasegna borders Italy. Despite its altitude of 686 m. (2250 ft.), the village enjoys a mediterranean climate. Palms, figs, camellias and grapes grow in the small, manicured gardens throughout the village.
From above, Castasegna is a sea of stone roofs with only the bell tower of St. Trinity Church, built in 1660, rising above. Nearby, towards the Maira River, is another church, St. Giovanni Battista, mentioned for the first time in 1409. The cobblestone main street is lined with magnificent houses, built in the 17th century, and Villa Garbald is the only building south of the Alps constructed by architect Gottfried Semper.
Off of the main road, and up through the narrow paths and alleys one catches traces of the old farming community that once existed, such as the fountains previously used for washing clothes and linens. In Brentan, just above Castasegna, is an extensive chestnut forest, one of the largest in Europe that is still cared for and cultivated in a traditional manner. Under these magnificent chestnut trees, there is an interpretive trail, which winds through the landscape of traditional "cascine" (huts used for drying and smoking the chestnuts). Architect Bruno Giacometti designed the small group of houses in Brentan and the red customs building on the border.