The increase in the delinquency caseload handled by juvenile courts has driven the growth in the number of juveniles in the detention system. In 1989 juvenile courts handled 1.2 million delinquency cases. By 1998 this number had increased 44 percent, to nearly 1.8 million. The increase in the volume of cases entering the juvenile justice system resulted in a 25-percent increase in the number of delinquency cases that involved detention at some point between referral and case disposition. The most dramatic change in the detention population between 1989 and 1998 was the influx of female juveniles charged with person offenses. Generally, the proportion of delinquency cases ordered to detention remained relatively steady between 1989 and 1998; however, there was a 56-percent increase in detention for females compared with 20 percent for males, with the increase for females related primarily to person-offense increases. Detention caseloads increased more for white juveniles than Black juveniles, in part because the use of detention in cases that involved person and drug offenses increased more for whites than Blacks. Although detention for juveniles charged with person offenses was three times greater for whites than Blacks and the increase for drug offenses was 12 times greater for whites than Blacks, Black juveniles were still more likely to be detained than white juveniles for every year between 1989 and 1998. This was true for all offense categories. With the exception of drug offenses cases, the use of detention remained relatively constant from 1989 through 1998. For most age groups, the use of detention decreased slightly between 1989 and 1998. The data indicate that although more young children (age 13 and younger) were in the juvenile justice system in 1998 than 10 years earlier, the proportion of cases that involved detention in this age group declined during this period. 1 table and 2 figures