The Campano-Lucano Arch is a major hydrocarbon province in the Southern Apennines of Italy. To provide new understanding of the thrust-belt architecture while constraining the derived interpretation of buried structure, we have analyzed data from seismic-reflection, wells, surface geology, 3-D computerized reconstructions, and sandbox simulations and integrated these data into a regional-scale structural model. Results show that refolding of already folded and thrusted units models the current structural setting, in which shallow and deep structures interact to form the recognized tectonic framework. In the region, recent folding and thrusting of the deeper autochthonous substratum reworked an early-phase vertical allochthonous assemblage, which ultimately behaved like a new pseudo-multilayered stratigraphy. Three-dimensional strain partitioning is moderately homogeneous across the thrust belt's internal domain, because shallow and deep structures show minor mechanical disharmony. Conversely, distribution of the deformation is strongly inhomogeneous across the thrust belt's external and marginal domains, both vertically and horizontally (along strike). Interference, through time and space, between the related noncylindrical, shallow (the Apenninic Thrust Belt) and deep (the Apulian Thrust Belt) contractional systems has developed a dome and basin structural pattern that characterizes the current tectonic architecture and that may localize, at depth, the main oil accumulations in the region.