The Adolescent Brain Cognitive Development (ABCD) Study® is the largest long-term study of brain development and child health in the United States. The National Institutes of Health (NIH) funded leading researchers in the fields of adolescent development and neuroscience to conduct this ambitious project. The ABCD Research Consortium consists of a Coordinating Center, a Data Analysis, Informatics & Resource Center, and 21 research sites across the country (see map), which have invited 11,880 children ages 9-10 to join the study. Researchers will track their biological and behavioral development through adolescence into young adulthood.