The Children’s Bureau, within the Administration for Children and Families, funded a multi-phase grant program to build the evidence base on what works to prevent homelessness among youth and young adults who have been involved in the child welfare system. Known as Youth At-Risk of Homelessness (YARH), this program funded 18 organizations for the first phase for two years. During the planning phase, grantees conducted data analyses to better understand their local population and develop comprehensive service models to improve outcomes in housing, education and training, social well-being, and permanent connections. During the initial implementation phase, grantees are refining and testing their comprehensive models. This issue brief discusses the rationale for the YARH grant program and the supports the Children’s Bureau provides the grantees through the multiple phases.