The municipality covers an area of about 22 square kilometers along a mostly flat territory. There are, however, six hills that characterize the town of Osoppo (the 3 main reliefs the Fort of Osoppo, the Colle di San Rocco and the Col Vergnâl).

Historically were found traces of pre-Roman times. The area was populated , in the old-age, by the tribe of Carni, that are part of the Celtic and settled all over Friuli. In fact are evident traces left by Celtic language in the current  Friulian language and in culture and traditions of the Friulian people.

Count Girolamo Savorgnan discovered an inscription near the Via Julia Concordia where it merges with the Via Julia Augusta and someone supposed that is an indication of the probable existence of the Via Etruscan (the importance of this inscription is not in the meaning but in the writing, before the Roman era). The presence of important transport routes determined the building of a signal tower on the hill and therefore a settlement.

It was closely related in any period with the most famous hill, called “the Fort”, which was used for centuries due its strategic position as an element of military defensive system, both as a place for control of the streets that cross the plain.

Osoppo passes through different periods under the domination of the Romans, the Barbarians, the Republic of Venice, the austro-Hungarians until becoming a symbol of resistance during the two world conflicts.

During the seventies it reached a good level of economic development with the establishment of the industrial zone, but the earthquakes of 1976 inflicted another blow to the town with immense damages, destroying 80% of homes and killing more than 120 people. Many collapses were favored by old age of the buildings, which had been spared from the ravages the World Wars. After the earthquake Osoppo was completely rebuilt with seismic criteria.

The best image that this country wants to give is that of a peaceful small provincial town that can offer events, services, and international festivals, industries, environmental protection for a good quality of life for residents. In fact the population is constantly growing, and this is the best sign of the vitality of the town.