The first magnetic observations in the Ross Dependency were made by Sir James Clark Ross in 1840. Since then various expeditions have carried out magnetic measurements, but until the beginning of the International Geophysical Year (IGY) the results were scanty. During and since the IGY much magnetic information has been accumulated for this area, on land, in the airs and at sea. An analysis of this information is presented, from which it is clear that satisfactory estimates of the secular variation can be obtained only by continuing the magnetic observatories established during the IGY. The change in total magnetic force since the days of Ross is shown by comparing his chart with one published by Adams and Christoffel for 1958–60.