The 1986 probations population showed a 6.4-percent gain over 1985, with the highest gains in the Northeast and the lowest in the West. Six States reported increases over 12 percent, and six showed decreases ranging from 1 to 2.7 percent. The parole population grew about 8.9 percent over 1985. From 1979 to 1985, the parole population increased more slowly than the probation population, but this trend was reversed in 1986. Seven States reported increases over 20 percent, with the largest increases being in the South and West and the lowest in the Midwest. A decline in the parole population, averaging 7.3 percent, was reported by 15 States. During 1986, the number of persons under correctional supervision (incarcerated or under community supervision) reached a new high of 3.2 million, a 7-percent increase over 1985 and a 30-percent increase since 1983. About 1 out of every 55 adults in the United States was under some form of correctional supervision on a given day in 1986. Additional State-by-State data are provided. 4 tables.