NOAA Logo, NOAA Satellites and Information, National Geophysical Data Center (NGDC).

 NOAA > NESDIS > NGDC > Geomagnetic Data Home
Geomagnetic Data and Services at NGDC
artistic rendering of geomagnetic field
artistic rendering of geomagnetic field

Calculate Declination

The study of geomagnetism is one of the oldest of the geophysical sciences. Since before the publication of William Gilbert's De Magnete in 1600, people have tried to unravel the mysteries of Earth's magnetic field. 

The National Geophysical Data Center maintains archives of geomagnetic data to further the understanding of Earth magnetism and the Sun-Earth environment. Data at NGDC include surface, ocean, airborne and satellite measurements, as well as models of the main field and its secular change, and models of the Space - Earth environment. Data on Earth's ancient magnetic field are available from archeomagnetic and paleomagnetic measurements. For those interested in learning more about geomagnetism, we have a general information page, a Frequently Asked Questions (FAQ) page, and a site focusing on the joint research with the Cooperative Institute for Research in Environmental Sciences (CIRES).

NewOn-line US Historic Declination (1750-2010) Calculator.