The borough of Canzo is situated in front of the Valassina valley, beginning at the foot of the Corni di Canzo mountain, so called (Corni meaning Horns) for its crest, as bifurcate and rocky, ash-grey, in the shape and color of two horns. After the plain of Erba, Canzo is at the confluence of the two small valleys formed by Mount Barzaghino, Mount Scioscia and Mount Cornizzolo. The first is the site of Lake Segrino, formed by glacial movements. The second hosts the town of Caslino. An intermittent spring rises from the side of Corni di Canzo and flows into the river Lambro, whose waters flow south to the Brianza region, pass Milan and reach the Po River. Elevations range from 360 to 1,371 m above sea level.