After the middle of the sixteenth century, some of the inhabitants descended to the valley to erect permanent housing there, giving rise to the frazioni Roccasecca Centro, Castello, and Caprile.

In the ensuing centuries the rocca of Roccasecca passed between the Angevin kings of Naples or the Aragonese, in intermittent contention with the Papal States, for the resulting power over the Valle del Liri.

After the unification of Italy in 1860 and the arrival in 1902 of a railroad line to Avezzano that linked Roccasecca with the larger world, emigration to the industrial north and farther abroad became more practical.

The war was a tragic episode: Roccasecca was chosen, due to its rail station and railroad bridge across the Melfa, as the headquarters for the German XIV Panzer Corps under General Fridolin von Senger und Etterlin, with the consequence of repeated Allied bombing, which heavily damaged the commune's population and culminated in a ferocious attack on the rail station.

In the post-war period, reconstruction brought some industry for the first time and modern redevelopment in the demolished area around the restored railroad station.