A study of the statistical structure of an aeromagnetic field over approximately four and a half thousand square miles of the Parry Sound and Huntsville area of southern Ontario has revealed the following: From the point of first‐order statistics, that is, mean, variance, skewness, and probability distribution function, the right half of the area which is occupied by hornblende or biotite migmatite is homogeneous and Gaussian, whereas the left half, which is mainly occupied by amphibolite gneiss, is generally inhomogeneous and non‐Gaussian. From the point of view of second‐order statistics, that is, the spectrum, the entire field appears to be inhomogeneous. This difference between statistical pictures is attributed to the fact that there are at least two preferred directions of strike, which influence the shape of the spectrum significantly.