Data for this study were obtained from jail registers for Owen Sound in rural central Ontario, for Kenora in northern Ontario, and for the Ontario reformatory for women; from local histories and newspapers; and from the annual reports of the inspector of prisons and asylums for Ontario from 1857 to 1931. Findings show that women received longer sentences and served longer terms in the Mercer Reformatory than in either of the rural jails. These differences were significant; on average, women sentenced to Mercer received 335 days, and women sentenced to the Owen Sound jail received 154 days; women sentenced to the Kenora Jail received 68 days. Women committed to Mercer for the first time received longer sentences than women who had been previously committed and served longer periods of time in the institution. The longer sentences at Mercer resulted from its reform agenda, which took young first offenders, who were thought to require long periods of incarceration, and attempted to transform them into the institution's ideal of the proper woman. The jails had no such commitment to reform, and the courts were more reluctant to incarcerate women in them. Government parsimony may also have influenced sentencing decisions. The greater costs of running jails compared with penitentiaries was a recurrent theme in the annual reports of the inspector of prisons and asylums. The penal philosophy of the time had a significant impact on the sentences the women received as well, and the time they served. With a move away from the classical belief in individual responsibility and moral weakness to a belief in scientific reform and a reliance on environmental explanations of crime, the progressive era brought demands for indeterminate sentences, probation and parole, and educational and vocational programs for inmates. At Mercer this meant that more women were given longer, indeterminate, or indefinite sentences; they served longer periods in spite of the increasing use of parole. 80 notes