The facilities were all constructed and opened since 1980, and the sample covered the full range of California counties and the full variety of facility types. The study addressed direct costs, including personnel salaries and benefits, services and supplies, and contract services with the private sector or with other county departments. Examples of costs not included include debt financing, litigation defense and liability payments, county overhead allocable to detention, and "opportunity costs" from diverting land and funding to detention from other uses. Findings indicate that total jail operating costs in California rose by 55 percent from 1984-85 to 1987-88. By 1987-88 the total local detention operations cost was $720 million, approximately $25.70 per citizen per year. Costs per inmate in the facilities studied averaged approximately $39 per day in high-security pretrial facilities and $28 per day in dormitory-style facilities housing mostly sentenced inmates. Costs per citizen were closely correlated with incarceration rates; the higher the incarceration rate in a county, the higher the bill to each taxpayer. Among the systems studied, those using nonsworn custody staff had the highest cost per inmate and the fewest inmates per staff. Conversely, systems that used only sworn custody staff had, as a group, the lowest cost per inmate and the most inmates per staff. This article provides information on staffing, cost factors, life-cycle costs, and revenues.