Interstate migration has decreased steadily since the 1980s. We show that this trend is not primarily related to demographic and socioeconomic factors, but instead appears to be connected to a concurrent secular decline in labor market transitions. We explore a number of reasons for the declines in geographic and labor market transitions, and find the strongest support for explanations related to a decrease in the net benefit to changing employers. Our preferred interpretation is that the distribution of relevant outside offers has shifted in a way that has made labor market transitions, and thus geographic transitions, less desirable to workers.