A comprehensive data set of more than 200 profiles across the Peru-Chile Trench between 4° and 45°S is used to describe the morphology and shallow structure of the trench axis and the downbending oceanic plate just prior to subduction. Five morphotectonic provinces (4°–12°, 12°–17°, 17°–28°, 28°–45°S) show distinct changes in trench depth, axial sediment thickness, oceanic plate fault structures, and dip of the seaward trench slope. In general, the northern and southern regions are characterized by relatively shallow axial depths, moderate to thick trench axis turbidites, and a gently dipping seaward trench slope that exhibits minor normal faults. The deeper...