The US Immigration and Customs Enforcement operates the largest detention system in the world, holding over 35,000 people in October 2023. The vast majority of this capacity is outsourced to corrections firms, particularly the two largest, CoreCivic and GEO Group. This article analyses how private corrections firms finance US immigrant detention capacity as a specialised asset class of government real estate. To understand the emergence of “carceral real estate”, I bring political geographies of migration into conversation with economic geographies of real estate. In doing so, I argue that creating “carceral real estate” enables the abstraction and valuation of migrant life as rent and, in turn, presumes a continuously flowing, fungible migrant population. In this context, migrants valued as underpaid labour in the wider economy are re‐valued for their unproductivity in detention. And yet this idealised geography of human and economic flows never fully materialises, but is instead rife with volatility, disruption, and political contestation. The article closes by discussing implications for abolition geographies.