The death of a parent or sibling during childhood is an adverse experience that increases risk for future behavioral health, academic, and relational problems, as well as earlier mortality. Efforts to estimate childhood bereavement prevalence rates have been hampered by methodological, reporting, and data source limitations. In the absence of national tracking systems in the United States, a quantitative statistical model has been introduced with the aim of estimating the prevalence of this public health issue to aid in needs assessment and service provision. A hybrid of binomial probability and life table methods was applied to develop the Childhood Bereavement Estimation Model (CBEM), which utilizes U.S. vital statistics data to generate current and projected estimates of the number of youth impacted by the death of a parent or sibling. National and state CBEM estimates are reported. Notable differences among geographies and associated public health implications are discussed, contextualizing childhood bereavement among other social determinants of health and calling for a more comprehensive approach to this underresourced issue. Nationally, CBEM Projected Estimates reveal that 6.99% of children—nearly 5.0 million—have or will have experienced the death of a parent or sibling by age 18. For youth under 25, this estimate more than doubles to almost 12.9 million. The CBEM offers social service professionals a tool for raising awareness about the magnitude of childhood bereavement and assessing the need for grief services within specific localities to ultimately equip communities in developing effective preventive interventions that are inclusive and accessible. (PsycInfo Database Record (c) 2020 APA, all rights reserved)