It is located on the shore of the Lake of Barrea, a lake created after World War II due to the building of a dam on the River Sangro.
The village of Barrea descends from the pre-Roman population of the Sannitis, who linked their destinies to the village. Currently, along the shores of the lake or in the nearby archaeological site of Alfedena, traces abound from this period. There is a document from the year 996 in which the ancient name of Barrea, Vallis Regia, first appears. This document also mentions that Barrea was given to the Duke of Spoleto during the dark feudal times in Italy, a period noted for its anarchic regimes and barbaric raids.
Perhaps mainly to protect themselves from the fierce raid of the Unnis, the inhabitants of the valley floor sheltered near a Benedictine monastery in a strategic position on the precipice of the river Sangro. Even today the monastery still exists and has withstood the ravages of man and the assault of time and the elements. In the following centuries, the inhabitants of Barrea built a tangle of practically impregnable houses along the southwestern side of the valley. Everything is protected by nature on one side and by observation towers, one round and one square, and defensive walls on the other. Historic records of this town mirror other examples found in Italy: bloody wars, rivalries and even devastating earthquakes.
One side of the original, central castle was protected from invaders by natural means, utilizing the impassably steep slope of the mountain; two stone castle gates afforded other protection to the castle and the homes that were built within its walls, dug into the slides of the mountain and giving out through front entrances facing on narrow, twisting, steep stone alleys.