["Law & Society Review, Volume 54, Issue 4, Page 755-787, December 2020. ", "\nThis article introduces the concept of collective liminality, a shared condition of heightened threat and uncertainty experienced by immigrant detainees and their families, as they wait, caught between two possible outcomes: their loved one's (temporary or permanent) release into the US or deportation. Drawing on 2 years of ethnographic data collection between 2015 and 2017 that included accompanying families to visitation at three Southern California detention facilities, and in‐depth interviews with former detainees and their relatives, I demonstrate the broader “collateral consequences” that immigration detention inflicts on detainees' loved ones. I find that not only does the detained individual experience liminality, but the detention of a loved one places the family in a state of shared liminality, which is experienced at two levels: material and emotional. These hardships materialize even before the detainees' deportation and can persist even after their release back into the US. This research extends scholarship on the impacts of detention on detainees, and on the consequences of deportation for families. The concept of collective liminality highlights how immigration detention functions as a critical tool of immigrant surveillance, punishment, and exclusion.\n"]