In each hemisphere at the core/mantle boundary, there are patches of magnetic flux with a polarity opposite to that of the dominant flux for that hemisphere. These patches account for most of the secular variation of the geomagnetic field and may provide an explanation for larger-scale, longer-term behavior. In this project, the behavior of the geomagnetic field will be modelled using flux patches at the core/mantle boundary. The interactions of the flux patches will be treated as a problem in Ising model theory.