These digitized aeromagnetic datasets from the US Geological Survey show variations in the Earth's magnetic field caused mostly by the distribution of minerals that make up the upper part of the earth's crust. The data may be accessed by clicking on the name of a state or territory. Users can download data for an entire state or obtain files by clicking on state maps showing location plots.

Anyone researching or interested in geomagnetism will appreciate the US Geological Survey's Geologic Hazards: Geomagnetism Web site. Visitors will find research publications, various downloadable magnetic charts, models, data plots, an online calculator for magnetic fields, and more.