This article explores how injuries, sickness, and the geographic mobility of Union Army veterans while in service affected their postservice migrations. Wartime wounds and illnesses significantly diminished the geographic mobility of veterans after the war. Geographic moves while carrying out military missions had strong positive effects on their postservice geographic mobility. Geographic moves while in service also influenced the choice of destination among the migrants. I discuss some implications of the results for the elements of self-selection in migration, the roles of different types of information in migration decisions, and the overall impact of the Civil War on geographic mobility.How did medical events and the geographic mobility of Union Army veterans while in service affect their postwar migration? The main purpose of the present research is to understand the effects of health and information on migration decisions in nineteenth-century America. It is widely accepted that information is a key determinant of geographic mobility and location choice, and that health is an important element of a person's human capital that can affect both the cost and benefit of migration. Only a few studies have explicitly investigated the effect of information on migration, and those have relied mostly on highly indirect measures of information, such as the extent of chain migration. Even less is known about the link between health and geographic mobility. To my knowledge, this study is the first to attempt to consider explicit measures of health and improved information together with other conventional variables on human capital attributes as determinants of migration.The longitudinal data on Union Army veterans used in this study provide a unique opportunity to examine the effects of health and prior mobility on migration. Military service during the Civil War seriously damaged the health of a large number of recruits who survived the war. Because most battles were fought in either border or southern states, recruits from the North were deployed to distant regions, and thus had opportunities to gain first-hand knowledge about other locations. Wartime medical experiences and geographic moves were unanticipated events, not related to the choice or characteristics of the soldiers. By exploiting these special features of wartime experiences, I can mitigate potential problems of endogeneity and selfselection bias commonly confronted by previous studies on migration. Also, the data allow a rare opportunity to examine the association between health and mobility at relatively young ages thanks to the wide variations in wartime medical experiences.My study deepens our understanding of the determinants of migration in the nineteenth-century United States in several ways. First, it provides the very first rigorous evidence of how particular wounds and diseases influenced the probability of migration and the choice of destinations among migrants in the nineteenth-century United States, where geographic mobility was exc...