The response to COVID-19 had an unprecedented impact on Wisconsin’s incarcerated population, as local jail and state prison populations plummeted during the pandemic after years of increases.

Local jail populations in the state declined by more than one-third last spring, according to new state data. Though the number of people in custody has risen somewhat in local jails since then, they are still 24% lower than they were a year earlier, state Department of Corrections figures show.

The data shows the combined populations of local jails and state prisons have fallen over the past year to their lowest levels in at least two decades. The decline reflects pre-pandemic local and state decisions to reform the criminal justice system, deliberate efforts to reduce populations to control the spread of the coronavirus, and the inadvertent effects of a slowdown in criminal trials during the pandemic.

Weekly data from the last Friday in each month showed the adult prison population declined 15.8% from the end of February 2020 to February 2021, from 23,251 to 19,581. The population fell in every month to hit the lowest point since October 1999.

The population in Wisconsin’s county jails dropped more sharply and rapidly, according to separate data that covers the inmates held in facilities in 71 of the state’s 72 counties. The offenders housed in those facilities typically are comprised mostly of those who are serving shorter sentences or awaiting a trial, transfer, or the next step in the justice system process. From April 2019 to April 2020, the average daily population in local jails declined by 35%, from 12,871 to 8,338. By December, local jails’ average daily populations had begun edging back up, by about 10%, not nearly enough to recover all their previous population.

It remains unclear whether inmate numbers in Wisconsin will return to pre-pandemic levels in the coming months. The manner in which this plays out will have financial impacts in a state that sharply increased its corrections spending and prison populations in the 1990s and remains above the national average in those respects. However, policymakers seeking to avert a rise in corrections populations to pre-pandemic levels should consider the effect on public safety as well as the impacts on local and state corrections budgets.

This information is provided to Wisconsin Newspaper Association members as a service of the Wisconsin Policy Forum, the state’s leading resource for nonpartisan state and local government research and civic education. Learn more at wispolicyforum.org.