In Colorado, commitments to corrections and the number of offenders under correctional supervision have increased from 1972 through 1982. The proportion of offenders supervised under various correctional alternatives, however, has varied over this period. The proportion of commitments to probation and the proportion of all offenders under probation has dramatically increased. The reverse is true for institutional corrections. As the total correctional population continues to grow, policymakers must determine how to control the growth in institutional populations. They could establish relative limits of growth for institutional corrections, so as to stabilize growth and provide a sound basis for future fiscal and program planning. This would involve analyzing both current and historical institutional data; projecting the future growth of the total correctional population; and analyzing comparative data on the incapacitation rates experienced in other States with similar populations, economies, and crime problems. A relative limit on the prison population is preferable to an absolute limit, because it permits the State to accommodate changes in the number of serious offenders that require incapacitation. Tabular and graphic data are provided.