A complete census of local jails is conducted every five years. In the intervening years, this sample survey provides basic data for the national jail population annually. The survey solicited information on the Nation's jail facilities and inmate population. The information provided in this booklet covers survey methodology, study purposes, data limitations, and standard errors for data items. The word and character record layout for each variable is presented. The coding format for each variable item is also outlined and explained. The questionnaire and the Entrex keying and output specifications for the jurisdiction-level file are provided.