This dissertation consists of two essays that study the determinants of geographical reallocation and their macroeconomic implications. In the first chapter (co-authored with Y. Fatih Karahan), we study the role of the aging population in the long-run decline of interstate migration in the United States. We argue that, in addition to a direct compositional effect on migration, the aging population has an indirect general equilibrium effect through the labor market. There is a positive composition externality of high-moving-cost workers on the local labor market: An increase in the fraction of high-moving-cost workers increases the local job-finding rate and reduces the migration rate of all workers. We label this effect as "migration spillovers." Our quantitative analysis suggests that population aging decreases the annual interstate migration rate by 0.9 percentage points, which accounts for 59 percent of the observed decline. Of this 0.9 percentage points, 78 percent is attributable to the indirect general equilibrium effect of the aging population and only 22 percent is due to the direct effect. In the second chapter (co-authored with Y. Fatih Karahan), we construct an equilibrium model of multiple locations with frictional housing and labor markets to study the effect of the housing bust on labor reallocation. The minimum down payment requirement makes it harder for homeowners to trade houses when house prices decrease. Consequently, the housing bust reduces migration and increases the unemployment dispersion. The model accounts for 90 percent of the increase in dispersion of unemployment and the entire decline in net migration. However, the effect on aggregate unemployment is moderate: absent the housing bust, aggregate unemployment would have been 0.5 percentage points lower.