Empirical and analytical techniques for modeling ionospheric fields in Magsat data have been developed that facilitate ionospheric field removal from uncorrected anomalies to obtain better estimates of regional lithospheric anomalies. This task has been accomplished for equatorial ΔX, ΔZ, and ΔB component and polar ΔZ and ΔB component measurements. The techniques for modeling ionospheric fields have been integrated into a processing sequence that incorporates some of the important data-processing techniques developed during the last decade. Data-processing techniques include retention of common signal in a correlation analysis of adjacent passes; analysis of field differences between dawn and dusk data at point where their orbits cross; and retention of common signal in a covariant spherical harmonic analysis procedure. Results suggest that implementation of the above processing scheme leads to the mapping of the most robust magnetic anomalies of the lithosphere (vector components as well as scalar). ¿ American Geophysical Union 1995