The U.S. immigration detention system is spread out across federal facilities, private prisons, state prisons, and county jails. It’s grown under both Democratic and Republican presidents. And it’s been offered up as a source of revenue for over a century, beginning with the first contracts between the federal government and sheriffs along the Canadian border. This episode originally published in September 2025. Guest: Brianna Nofil, assistant professor of history at The College of William and Mary author of The Migrant's Jail: An American History of Mass Incarceration To access bonus episodes and listen to Throughline sponsor-free, subscribe to Throughline+ via Apple Podcasts or at plus.npr.org/throughline. To manage podcast ad preferences, review the links below: See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy