For perhaps the first time since the founding of the United States the net direction of interstate migration was to the east rather than the west for the period 1992–1993 through 1994–1995. This and other findings, such as a general slowdown in the southward tendency of U.S. population movement over the period 1980–1981 to 1994–1995, are highlighted using the concept of migration drift. I propose the migration drift measure to summarize the net directionality and distance moved by migrants in any country's population system. Like the concept of a center of population or a population centroid, migration drift is an intuitive one. Unlike the population centroid, however, migration drift summarizes the pure effects of population movement without confounding those influences with spatial variations in birth, death, and net foreign immigration rates.