Your information on the surveying and the western grid system is essentially correct. However, for various reasons, one section does not always equal one square mile. One big unavoidable reason is the curvature of the earth. As one travels north,approaching the poles, the longitude lines converge, thereby compressing the distance between the north and south sides of a section. This problem was generally accomodated by periodically adjusting the size of individual sections. For this reason, the north- south sides of some sections may not run exactly north and south. Al Bass, (former) Registered Land Surveyor (ret.)