High-resolution aeromagnetic data from the Nigeria Geological Survey Agency (NGSA) were processed to produce the most spatially detailed lineament map of the Ijebu-Ode region in southwestern Nigeria to date. Reduction to the Equator (RTE), Analytic Signal Amplitude (ASA), and Euler deconvolution (structural index = 1) were applied to identify major and minor fault-related lineaments with high positional accuracy. The resulting structural map delineates numerous NW–SE and NE–SW trending lineaments consistent with regional tectonic fabrics, indicating continuity between surface and subsurface structures. The integrated analysis quantifies lineament orientations, densities, and patterns, providing a robust framework for geological mapping, groundwater exploration, and mineral prospecting. This work addresses a significant knowledge gap in basement complex mapping by applying modern aeromagnetic processing and offers a replicable workflow for similar terrains globally.