This report defines a jail as a "locally administered confinement facility that holds persons pending adjudication or persons committed after adjudication, usually for sentences of a year or less." Local jails held 343,569 persons on June 30, 1988, 54 percent more than in 1983, the year of the last National Jail Census. There were 144 inmates per 100,000 U.S. residents, 47 percent higher than in 1983. The number of female inmates nearly doubled (93 percent) since the last census, and the male inmate count rose 51 percent. Of the inmates discharged in the week preceding the census, the median length of stay was 3 days. Jail space, as measured by the number of beds or inmates assigned by a State or local rating official, increased by nearly two-fifths between 1978 and 1988. For the Nation as a whole, the jail population was 101 percent of the rated capacity, up from 85 percent in 1983. Twelve percent of the jails were under Federal or State court order or consent decree to limit the number of inmates. AIDs accounted for 10 percent of 667 inmate deaths during the year ending June 30, 1988; and suicide accounted for 43 percent of deaths. Other data cover number of jail employees and jail expenditures. 24 tables.