Mental health encompasses a range of mental, emotional, social, and behavioral functioning and occurs along a continuum from good to poor.Previous research has documented that mental health among children and adolescents is associated with immediate and long-term physical health and chronic disease, health risk behaviors, social relationships, education, and employment.Public health surveillance of children's mental health can be used to monitor trends in prevalence across populations, increase knowledge about demographic and geographic differences, and support decision-making about prevention and intervention.Numerous federal data systems collect data on various indicators of children's mental health, particularly mental disorders.The 2013-2019 data from these data systems show that mental disorders begin in early childhood and affect children with a range of sociodemographic characteristics.During this period, the most prevalent disorders diagnosed among U.S. children and adolescents aged 3-17 years were attention-deficit/hyperactivity disorder and anxiety, each affecting approximately one in 11 (9.4%-9.8%)children.Among children and adolescents aged 12-17 years, one fifth (20.9%) had ever experienced a major depressive episode.Among high school students in 2019, 36.7% reported persistently feeling sad or hopeless in the past year, and 18.8% had seriously considered attempting suicide.Approximately seven in 100,000 persons aged 10-19 years died by suicide in 2018 and 2019.Among children and adolescents aged 3-17 years, 9.6%-10.1% had received mental health services, and 7.8% of all children and adolescents aged 3-17 years had taken medication for mental health problems during the past year, based on parent report.Approximately one in four children and adolescents aged 12-17 years reported having received mental health services during the past year.In federal data systems, data on positive indicators of mental health (e.g., resilience) are limited.Although no comprehensive surveillance system for children's mental health exists and no single indicator can be used to define the mental health of children or to identify the overall number of children with mental disorders, these data confirm that mental disorders among children continue to be a substantial public health concern.These findings can be used by public health professionals, health care providers, state health officials, policymakers, and educators to understand the prevalence of specific mental disorders and other indicators of mental health and the challenges related to mental health surveillance. USDepartment of Health and Human Services/Centers for Disease Control and Prevention provisions for children with preexisting conditions (e.g., the Mental Health Parity and Addiction Equity Act and the Patient Protection and Affordable Care Act) (51-54).This report updates and expands the 2013 surveillance report on mental health among children (8).Similar to the 2013 report, this report provides an overview of nine federal surveillance systems that collect data related to children's mental health in the United States and the most recent estimates (2013-2019) available from these systems, including estimates according to selected sociodemographic characteristics linked to social determinants of health, such as age, sex, race and ethnicity, economic resources, parent education, access to health insurance, and geographic classification ( 23).In addition, whereas the 2013 report focused on national estimates of mental disorders and indicators of poor mental health among children, this report also includes data on 1) receipt of mental health services among children, 2) positive indicators of mental health, and 3) state-level estimates.First, this report includes data on receipt of mental health services among all children.These data are an indicator of the impact of mental disorders or symptoms of mental disorders on the service system, the costs associated with mental disorders, and access to specialized health services.Describing patterns of mental health services by subgroups might identify gaps in access to services or treatment for mental disorders and provide information to address health inequities (30,55,56).Second, this report includes several positive indicators of mental health that are measured on a continuum to provide a more inclusive picture of children's mental health status.Third, this report includes state-level estimates when possible.State estimates are important because they describe the heterogeneity of smaller geographic units, can reflect the results of state-level practices and policies, and provide actionable information for program planning and resource allocation at a more local level (57,58).The findings in this report can be used by public health professionals, health care providers, state health officials, policymakers, and educators to understand the prevalence of specific mental disorders and other indicators of mental health and the challenges related to mental health surveillance.MMWR / February 25, 2022 / Vol.71 / No. 2 US Department of Health and Human Services/Centers for Disease Control and PreventionTABLE 1.Federal surveys and surveillance systems that collect data on children's mental health -United States Name, website, sponsor Description Method of data collection Topics related to children Child-related mental health topics and questions Populations and periodicity