Summary Interpretation of ground magnetic data from the south-central Alberta Foothills shows good correlation with airborne anomalies and the magnetic susceptibilities measured from the surface geology. Amplitudes of the residual ground magnetic anomalies are approximately an order of magnitude higher than the airborne data and contain more detailed information. Shale-dominated Upper Cretaceous and Lower Tertiary strata exhibit low amplitude residual magnetic anomalies (±1 nT), contrasting with the sandstone-dominated Middle and Upper Cretaceous rocks, which display higher intensity magnetic anomalies (±10 nT). Thrust faults, which commonly are located in more ductile strata, exhibit weak magnetic anomalies but are mapped well by horizontal and vertical derivatives of the ground magnetic data. The magnetization models constructed to reproduce the magnetic anomalies closely match both ground and airborne observed values.