Factors examined for their possible relationship to imprisonment rates were crime rates, sentence lengths, probation rates, unemployment rates, per capita income, and racial composition. Imprisonment rates were found to vary considerably by circuit court district, from a low of 91 per 100,000 population to a high of 253. No statistically significant relationships (at the .05 level or below) were found between imprisonment rates and average sentence lengths (considered four separate ways), probation rates, unemployment rates, per capita income, and racial composition. Crime rates could not be computed for the circuit court districts because of inadequate data. Imprisonment rates by county vary from a low of 34 to a high of 298. A relatively modest positive relationship was found between crime rates and imprisonment rates in the 57 counties for which crime rates were available. This finding is too weak to support definitive interpretation. Unemployment rates, per capita incomes, and violent crime rates were found to have no statistical relationship to imprisonment rates. Counties using probation at a higher rate were also found to use imprisonment at a moderately higher rate. The study's inability to determine solid causal explanations for the variation in imprisonment rates within Mississippi suggests the explanations lie in factors not easily subjected to statistical analysis, such as the discretion used by criminal justice personnel at every step in criminal justice processing. Tabular data and 39 footnotes are provided. For an addendum that examines the relationship between variations in imprisonment rates in Mississippi and degree of urbanization, see NCJ 82307. (Author summary modified)