With over 43 million family caregivers living in the United States, families are the largest providers of informal care in this country. Despite the extensive caregiving literature about prevalence, characteristics of care providers and care recipients, risks to caregivers' health and well-being, economic costs, impact on personal and family well-being, evidence-based interventions, and model community-based programs and supports for adult caregivers, gaps exist, specifically relating to caregiving youth, i.e., children under the age of 18 years. With no previous comprehensive review to assess what is known about US youth caregivers, a scoping review, focusing on mapping the key concepts, including the main sources and types of evidence available, was undertaken. By drawing conclusions about the overall state of research activity and identifying research gaps and priorities in the existing literature, this study provides a baseline assessment of youth caregiver research published in peer-reviewed journals from 1996 to 2015. A total of 22 articles were included in the analysis. Beyond inconsistencies with naming and defining young/youth caregivers, the review found significant knowledge gaps in crucial areas including SES status of families who rely on caregiving youth, the role of race, ethnicity and culture, support across schools, communities and medical professions, and the lack of caregiving programs and polices inclusive of youth under 18. The results underscore the need for further inquiry, including longitudinal study, into the lives and experiences of caregiving youth, informing the development of youth caregiver focused supports and polices across the US.