The McLean County Jail had multiple roles largely determined by the many disparate inmate groups housed. The jail was one of several social control measures used with the disadvantaged, the disturbed, and the deviant, including city ordinance violators, alcoholics, delinquents, prostitutes, gamblers, bad drivers, petty thieves, and the insane. The jail also handled some serious offenders. The separation of the sexes doubled the offender classifications. Extant jail registers provide demographic, offense, and processing information on the 21,000 persons held in the facility from the end of 1918 to December 31, 1941. This study reviewed data for all 1,765 female admissions and for a random sample of 3,530 male inmates that composed 17 percent of the total male admissions. Juveniles composed 14.7 percent of the jail population over the period. Study information on the female inmates covers occupation, race, age, birthplace, admission offense, and the number and destination of transfers. Similar information is presented for the male inmate sample. During the period studied, the jail responded reasonably well, albeit perfunctorily, to the multiple demands placed on it. The jail population was so heterogenous and changeable, however, as to make long-term planning and innovative programming impossible and the provision of basic services difficult. 32 references.