This paper examines the role of labor market frictions and moving costs in explaining the migration behavior of US workers by employment status. Using data on low-skilled workers from the Survey of Income and Program Participation (SIPP), I estimate a dynamic model of individual labor supply and migration decisions. The model incorporates a reduced-form search model and allows for migration for non-market reasons. My estimates show that moving costs are substantial and that labor market frictions primarily inhibit migration of the employed. I use the model to study migration responses to local labor market shocks and to a moving subsidy. Workers' preferences for non-market amenities, coupled with substantial moving costs and employment frictions, grant market power to incumbent employers. Large moving costs also likely affect employers' recruiting behavior.