An increasingly important goal of state policymakers is to keep young, well-educated adults to remain in that state instead of moving elsewhere after college, as evidenced by New York's recent move to tie state grant aid to staying in state after graduation. We used American Community Survey data from 2005-2015 to examine the prevalence of interstate mobility over the past decade as well as provide state-level rates of "brain drain." We found substantial variations in interstate mobility across states, which has important policy implications.