A limited number of recent empirical studies suggest that inmates suff
er from high rates of serious mental illness. Different explanations a
re offered depending on the type of institution: jail or prison. The l
iterature is based largely on urban samples and does not offer compari
sons of rates across types of institution within a single study. The p
resent study examined a random sample of 213 jail and prison inmates i
n a rural state using the Diagnostic Interview Schedule (III-R). Among
jail inmates there was little evidence of high rates of serious menta
l illness, suggesting the criminalization of mental illness may not be
as evident in rural settings as urban areas. Among prison inmates, ho
wever high rates of mental disorders were found, supporting previous f
indings in urban and rural jurisdictions. Implications of the findings
are discussed in the context of a consolidated correctional system.