The implementation of the Affordable Care Act (ACA) has set off reforms in health care systems across the country, including in county jails. Ninety percent of people who enter county jails have no health insurance. Prior to arrest, 60 percent of the jail-involved population has income low enough to qualify for expanded Medicaid, with another 33 percent qualifying for subsidized insurance through the Health Insurance Marketplace. Additionally, jail inmates suf- fer from chronic health conditions at a higher rate than the general population and 64 percent experience mental illness. More than 76 percent of those with a mental problem also suffer from substance dependence or abuse, as does 53 percent of the general jail population.5 Many of those who cycle in and out of county jails may now be able to obtain health insurance through the Health Insurance Marketplace or expanded Medicaid. County jails are therefore in a unique position to connect those in their custody with health insurance during pretrial detention or prior to discharge. Evidence suggests this could contribute to reduced health care and criminal justice costs to the county and lower jail operating costs. This brief will answer some of the most commonly asked ques- tions about the ACA and how it relates to county jails.