This week's edition of Mapping Mass Migration features an analysis of newly released data from the Census Bureau, its March supplement of the Current Population Survey. Our analysis covers how migration trends have played out nationally since 1948, including the demographics of movers, the extent of their migration (within a county, across counties, to another state, etc.), and the most common reasons movers cite for changing their primary residence. The newsletter concludes with a brief discussion of what might account for a decline in overall migration rates nationally and where Massachusetts fits in.