Arlena di Castro is a small agricultural town in the heart of Volsini mountains, located on the south west side of the volcanic landscape and furrowed by a variety of streams that form the river Arrone. Almost completely uninhabited and reduced to an ancient ruin, it was virtually refounded during the second half of the sixteenth century, at the behest of Cardinal Alessandro Farnese, who in 1573 installed there some families from Allerona.
Later the possession of the village passed from the Duchy of Castro and Ronciglioneto Count Alessandro Cardelli, by permission of Pope Pius VI, who then sold it to the Polish Prince Poniatowski. The economy of this small town is based mainly on the cultivation of wheat and olives, but also on products from the greenhouse and open field, such as tomatoes, asparagus, melon, watermelon and pepper.
Widespread is also the breeding of sheep although it is decreasing, mainly due to the crisis of the sector.
In the area there are also some active pumice quarries.