Off-lists, someone recently asked me about the Defective, Delinquent and Dependant Census of 1880. While I have used it many times, I have only been able to locate it at NARA in DC rather than online----I am confident it is also available in other repositories. Meanwhile, the online DOLLARHIDE census book tells all one needs to know about that and all the other U.S. census records, so I decided to provide the link. Mr. DOLLARHIDE explains far better than I. http://genealogyblog.com/proquest/dollarhides-the-census-book-is-online-and-free-5164