The geocentric axial dipole hypothesis states that the geomagnetic field, when averaged over tens to hundreds of thousands of years, corresponds to that of a dipole located at Earth's center and aligned with Earth's rotation axis. Accordingly, paleomagnetic poles, which are estimates of the position of the ancient dipole axis, give past positions of the Earth's rotation axis relative to a sample locality from which the paleolatitude of the sample can be derived. Using this hypothesis, paleomagnetists have established detailed paleogeographies for the continents that span several hundreds of million years. Such information is essential for understanding plate and terrane motions, mantle convection, paleoclimates, and geomagnetism, as well as many other subjects.