Although precise data on the numbers and characteristics of persons under 18 placed in jail are not available, a profile of such individuals based on 1977 and 1978 information is presented which considers time detained, types of offenses committed, referral source, sex, age, race, and prior court contacts. Some comparisons are included, such as a decrease in juveniles placed in jail for 24 hours or more from an estimated 500,000 in 1970 to 122,500 in 1977. The average length of stay for juveniles detained in jails during 1976 was 4.8 days as contrasted with 12 days for those sent to short-term public detention facilities. Statistics detail the numbers of States which permit detention of juveniles with adults in the same facility and those which have complied with Federal laws prohibiting this type of shared detention. Other subjects considered for the evaluation of jails versus nonsecure detention arrangements include runaways, recidivism rates, and costs in dollars per day. A cost analysis compares different combinations of separate jailing in secure facilities and home detention. The study concludes that, from an economic and pragmatic veiwpoint, all juveniles under 18 handled by the juvenile or criminal justice system could be detained outside a jail and that 90 percent could be placed in a nonsecure detention facility. A bibliography of 12 references is provided.