The federal government archives will not have state census records. The book, State Census Records, by Ann Lainhart indicates that Maricopa County had something called a "Great register" "registers of voters, much like census records because the data is similar" ... looks like perhaps for 1915, and suggests contacting Archives and Public Records, Arizona State Archives, Department of Library, Archives and Public Records, 1700 W. Washington, Phoenix Arizona 85007. Ann's book is copyrighted 1992.
