C. E. Kelsey's census of nonreservation Indians in Northern California in 1905 to 1906 was the first enumeration of its kind. It counted 11,755 Indians that were not supported by the US government, which was far more than were thought to exist. Intended as the blueprint for implementing Kelsey's proposed policy of providing federal relief through land purchases, the census was later used for population studies. The census lacks explanatory documentation and scholars have introduced errors to the population totals. Using archival sources, this article explores the context and purpose of the census and identifies those subsequent errors.