The population forecast pertains to inmates in prison and work release programs. Inmates boarded from other States or local jails are excluded. In fiscal year 1989 the inmate population is expected to reach the bottom of a decline that started in 1986. This decline is due to the increased number of releases rather than reduced admissions. This has resulted partly from a 1986 statutory change (SHB 1400) which requires the Indeterminate Sentence Review Board to review the minimum terms of all inmates not sentenced under the Sentencing Reform Act of 1981. The expected rapid growth in the inmate population after January 1989 results from the lower number of future releases under SHB 1400. Drug offenses are expected to cause a large increase in the inmate population. Other sources of increase are the new Automated Fingerprint Identification System, small increases in other crime types, other statutory changes, and State population increases. The long-range forecast shows steady growth in the prison population during the next decade. Under the simulation forecast model, the components of change are felony convictions, new prison admissions, recidivist prison admissions, and releases. Tabular data cover the long range inmate population forecast, including forecast by crime type; summary of assumptions in the 1989-91 population forecast; components of the inmate population; key indicators in the criminal justice system; monthly inmate population forecast; male conviction rates and judicial decision to imprison; and female conviction rates and judicial decision to imprison. 8 figures, 11 tables.