Erto e Casso (Standard Friulian: Nert e Cjas, locally: Nert e Cas) is a comune (municipality) in the Regional decentralization entity of Pordenone in the Italian region of Friuli-Venezia Giulia, located about 130 kilometres (81 mi) northwest of Trieste and about 40 kilometres (25 mi) northwest of Pordenone.

All the bordering municipalities, except Cimolais and Claut, are part of the nearby Province of Belluno, in Veneto.

The other hamlets, (frazioni), composed by few scattered farmhouses, are the localities of Forcai, Pineda, San Martino, and Val da Pont.

The landslide and flood killed almost 2,000 people in total, destroying five villages in the Piave valley but leaving Erto and Casso only slightly damaged.

Three years after evacuation, some other survivors, in spite of being forbidden to return to the valley, went back to their former houses and reformed the villages of Erto and Casso, which still form the municipality today.