The COVID-19 outbreak fueled unprecedented public health efforts to mitigate the spread of infection, including rapid provision of non-congregate housing to people experiencing homelessness. People on community supervision (criminal probation or parole) have high levels of homelessness due to housing discrimination, poverty and racism, and are among the groups most vulnerable to COVID-19. We examined housing status in a cohort of women with probation histories in Alameda County, CA before and after the COVID-19 outbreak (N=204). Before March 2020, 38% of women in the cohort reporting being homeless (95% CI: 34-43%), a level that was consistent over 2 years. As of August 2020, 15% of the cohort was homeless (95% CI: 10-20%; relative risk [RR] 0.40, 95% CI: 0.28, 0.55; p<0.001). During a period of assertive public health efforts to reduce COVID-19 risk through provision of housing, we found meaningful reductions in homelessness in this sample of vulnerable women.