The Child Opportunity Index 2.0 (COI 2.0) is a composite index measured at the census tract level that captures neighborhood resources and conditions that matter for children's healthy development in a single metric. The index focuses on contemporary features of neighborhoods that are affecting children. It is based on 29 indicators spanning 3 domains: education, health and environment, and social and economic. COI 2.0 data is available for virtually all U.S. census tracts for 2010 and 2015. COI 2.0 is based on COI 1.0 which was released in 2014. Please refer to the technical document for more detailed information on how COI 2.0 was constructed. Replication materials are available on the Institute's Github page.