This, the 31st annual National Child Count of Children and Youth Who Are Deaf-Blind, is the first and longest running registry and knowledge base of children who are deaf-blind in the world. Begun in 1986 on behalf of the U.S. Department of Education, it represents a thirty-plus year collaborative effort between the National Center on Deaf-Blindness (NCDB), its predecessors, and each state and multi-state deaf-blind project throughout the country, as well as projects funded in the Pacific Trust territories, the Virgin Islands, and Puerto Rico. Initially requested by the U.S. Department of Education as an examination of the discrepancy between the National Deaf-Blind Child Count and the Office of Special Education Programs' (OSEP) annual December 1 counts of children and students with disabilities being served under IDEA Part C or Part B, the child count has expanded over time to inform the work of a range of OSEP-funded deaf-blind projects during the ensuing years, including the current national, state, and multi-state technical assistance and dissemination projects. The National Deaf-Blind Child Count has been collaboratively designed, implemented, and revised to serve as the common vehicle to meet federal grant requirements for both the State and Multi-State Deaf-Blind Technical Assistance Projects and the National Deaf-Blind Technical Assistance Center, as well as serve as a common data collection and reporting mechanism for use across the country. [For the 2015 report see ED581439.]