Immigrants today in the UK, US, and elsewhere face rising uncertainty regarding both their ability to stay in their new country of residence and their right to access public goods. This uncertainty may affect not only the decision to migrate, but also the health, family planning decisions, and occupational and neighborhood choices of both immigrants and their children. This project uses a natural experiment in history to improve our understanding of the impact of this uncertainty on internal migration patterns, local labor markets, and the health and welfare of migrants. Specifically, we study the short- and long-run effects of legal changes in 1860s England that sharply reduced the risk of removal faced by poor migrants. We identify the effect of a reduction in uncertainty by interacting these policy changes with preexisting variation in the risk of removal. Thus, we exploit rich within-country spatial variation while controlling for fixed location effects. Our setting also allows us to track individuals over time using linked microdata, which is difficult in modern settings due to privacy concerns.