The relationship between neighborhoods of residence in young adulthood and health in mid-to-late life in the United States are examined using the 1968-2005 waves of the Panel Study of Income Dynamics (PSID). The sample consists of persons who were aged 20-30 in 1968 and are followed for a period of 38 years (N=2730). Four-level hierarchical random effects models of self-assessed general health status as a function of individual, family, and neighborhood factors are estimated. Using the original sampling design of the PSID, we analyze adult health trajectories of married couples and neighbors followed from young adulthood through elderly ages to assess the magnitudes of the possible causal effects of family and neighborhood characteristics in young adulthood on health in mid-to-late life. Estimates suggest disparities in neighborhood conditions in young adulthood account for one-quarter of the variation in mid-to-late life health. Living in poor neighborhoods during young adulthood is strongly associated with negative health outcomes in later-life. This result is robust even in the presence of a reasonably large amount of potential unobservable individual and family factors that may significantly affect both neighborhood of residence and subsequent health status. Racial differences in health status in mid-to-late life are also associated with family and neighborhood socioeconomic conditions earlier in life. Three quarters of the black-white gap in health status at ages over 55 can be accounted for by differences in childhood socioeconomic status and neighborhood and family factors in young adulthood.