The Federal Interagency Forum on Child and Family Statistics' primary mission is to enhance data collection and reporting on children and families. "America's Children: Key National Indicators of Well-Being, 2015" provides the Nation with a summary of national indicators of children's well-being and monitors changes in these indicators. The reasons for this report are to: (1) improve reporting of Federal data on children and families; (2) make these data available in an easy-to-use, non technical format; (3) stimulate discussions among policymakers and the public; (4) and spur exchanges between the statistical and policy communities. There are many interrelated aspects of children's well-being, and only selected facets can be included in this report. This report draws on various overarching frameworks to identify seven major domains that characterize the well-being of a child and influence the likelihood that a child will grow to be a well-educated, economically secure, productive, and healthy adult. The seven domains are: (1) family and social environment; (2) economic circumstances; (3) health care; (4) physical environment and safety; (5) behavior; (6) education; and (7) health. These domains are interrelated and can have synergistic effects on well-being. Each section of the report corresponds to one of the seven domains and includes a set of key indicators. These indicators either characterize an aspect of well-being or an influence on well-being. Appended are: (1) Detailed Tables; and (2) Data Source Descriptions. [This report was written by the staff of the Forum, including Traci Cook, Forum Coordinator; Rebecca Chenevert and Jonathan Vespa, Census Bureau; Patricia Pastor, LaJeana Hawkins, and Katherine Ahrens, National Center for Health Statistics; Grace Kena and Lauren Musu-Gillette, National Center for Education Statistics; Matthew Davis, Environmental Protection Agency; Barry Steffen, Department of Housing and Urban Development; Barbara Oudekerk and Rachel Morgan, Bureau of Justice Statistics; Meena Karithanom, National Institute on Drug Abuse; Mary Mueggenborg, Administration for Children and Families; Alisha Coleman-Jensen and Matthew Rabbitt, Economic Research Service; Lisa Williamson, Bureau of Labor Statistics; Shelli Avenevoli, National Institute of Mental Health; James Singleton and Cindi Knighton, Centers for Disease Control and Prevention; Beth Han, Substance Abuse and Mental Health Services Administration; and Hazel Hiza, Center for Nutrition Policy and Promotion.]