National health reform will expand insurance coverage by about 30 million people, reducing the number of uninsured by more than half. In this report, the authors analyze the likely composition, state by state, of those who will remain uninsured. Of the nonelderly adults uninsured under national health reform, 37% would be eligible for Medicaid but not enrolled and 25% would be undocumented immigrants. Sixteen percent would be exempt from the individual mandate because they had no affordable insurance option. The authors find significant state and regional variation in the characteristics of the uninsured.