We use novel, large-scale data on 17.5 million Americans to study how a policy-driven increase in economic resources affects children’s long-term outcomes. Using the 2000 Census and 2001-2013 American Community Survey linked to the Social Security Administration’s NUMIDENT, we leverage the county-level roll-out of the Food Stamps program between 1961 and 1975. We find that children with access to greater economic resources before age five have better outcomes as adults. The treatment-on-the-treated effects show a 6 percent of a standard deviation improvement in human capital, 3 percent of a standard deviation increase in economic self-sufficiency, 8 percent of a standard deviation increase in the quality of neighborhood of residence, a 1.1-year increase in life expectancy, and a 0.5 percentage-point decrease in likelihood of being incarcerated. These estimates suggest that Food Stamps’ transfer of resources to families is a highly cost-effective investment in young children, yielding a marginal value of public funds of approximately 62.