Sonogno lies at an altitude of 992 metres at the far end of the Valle Verzasca where the streams coming down from the Val Redòrta and Val Vegornèss converge. This is where the deciduous tree line ends; the last sweet chestnut, beech, alder, ash and walnut trees can be admired here. A further ascent through the narrow valleys – for instance to the remote Barone mountain lake – reveals an increasingly austere high-Alpine landscape.

Sonogno has retained its typical architectural character of historic houses and narrow alleyways. A typical building, the Casa Genardini, stands at the Piazzetta or small village square and houses the valley’s heritage museum. The old bakery which is still in use today stands nearby. At Frasco, close to the bridge crossing the stream running down from the Val d’Efra, the museum has restored to working condition an old watermill and a small electricity plant that supplied the valley with electricity since the 1920’s.

In the upper part of the village centre a farmhouse façade is embellished with a fresco depicting the Day of Judgment, painted in the 18th century by an unknown artist. A house at the entrance to the village shows another fresco depicting the Madonna, the village’s patron saint. Frescos are commonly seen throughout the Val Verzasca not only on and in churches but also on rock faces, houses and stables.

The Valle Verzasca is a rural and largely untouched valley with steep inclines and numerous waterfalls. The emerald-hued Verzasca River flows over bizarrely- formed, smoothly-polished rock through the narrow valley, forming several natural rock pools and places to bathe. The river is also popular with canoeists and divers but is regarded as difficult and in many places dangerous to navigate.

The «Sentierone» is an old pack mule route and mountain hiking trail that leads from the entrance to the valley along alternating banks of the Verzasca to Sonogno.