Flint (1) has shown the areal distribution of the Cary and Mankato glacial drifts in South Dakota. Studies of the distribution of soils in southern Hand County (2) make possible the refinement of the Mankato drift boundary in that area. Although the area in question is relatively small (approximately 95 square miles) when compared to the distribution of the two drifts in the state, it is a significant part of the county. The criteria used in relocating the boundary are: (1) kinds of soil profiles, (2) presence or absence of loess, (3) melt water channels and outwash, (4) composition of the tills and (5) moraines