A confinement facility generally operated under the authority of a sheriff, police chief, or county or city administrator. A small number of jails are privately operated. Regional jails include two or more jail jurisdictions with a formal agreement to operate a jail facility. Facilities include jails, detention centers, county or city correctional centers, special jail facilities (such as medical or treatment centers and pre-release centers), and temporary holding or lockup facilities that are part of the jail's combined function. Jails are intended for adults but can hold juveniles before or after their cases are adjudicated.