This paper examines the influence of transportation infrastructure on migration decisions in the context of the Great Migration in the United States. Focusing on the opening of the Panama Canal in 1920, we isolate the effect of improved economic opportunities from reduced migration costs. Using full-count Census data, we find that Southern African American migrants preferred areas with enhanced market access, leading to higher inflows after 1920. The study highlights the inter- play between migrant networks and labor markets in shaping migration patterns. Our findings underscore the significance of local market conditions induced by improvements in local market access in influencing migration decisions during the Great Migration.