The geologic map of the Tortolita Mountains encompasses the Tortolita Mountains 7.5’ quadrangle plus parts of 3 adjoining 7.5’ quadrangles; Desert Peak and Marana to the west and southwest, and Ruelas Canyon to the south. The Tortolita Mountains mark the northwestern extent of the Catalina metamorphic core complex (Davis, 1980; Banks, 1980; Keith et al., 1980; Dickinson, 1991; Force, 1997). Metamorphic and plutonic rocks of the complex were exhumed along a low-angle detachment fault of Mid-Tertiary age that is exposed along the southern edge of the Rincon and Santa Catalina Mountains and is inferred to lie buried beneath piedmont deposits along the southern edge of the Tortolita Mountains. A single small exposure of Middle Proterozoic Dripping Spring Quartzite on the southern piedmont of the Tortolita Mountains is interpreted to lie in the hanging wall of the Catalina detachment fault. This study documents a ductile shear zone in the northern part of the range, herein named the Carpas Wash shear zone, and a system of brittle normal faults that are interpreted as the northern continuation of the Catalina detachment fault system. Other important conclusions based on our mapping include: 1) recognition of a major, east-dipping normal fault bounding the western edge of a west-tilted sequence of volcanic rocks at Owl Head Buttes, 2) reinterpretation of a sequence of metasedimentary rocks near the head of Parker Canyon as Paleoproterozoic Pinal Schist instead of Mesoproterozoic Apache Group, 3) recognition of a north-dipping, top-tothe- west low-angle normal fault with an exceptionally wide and well-developed chloritic breccia ledge in its footwall along the western edge, 4) reinterpretation of the Cochie Canyon shear zone as a septum of Pinal Schist separating two major plutonic complexes, and 5) reinterpretation of a part of an easterly strand of the Guild Wash fault zone as a series of south-dipping reverse faults that cut the lower part of the Tertiary supracrustal stratigraphic sequence and that are overlain by Tertiary conglomeratic units.