During 2019, there was a surge in Southwest Border crossings between ports of entry, resulting in 851,508 Border Patrol apprehensions and contributing to what senior U.S. Customs and Border Protection (CBP) officials described as an “unprecedented border security and humanitarian crisis.” Our unannounced inspections revealed that, under these challenging circumstances, CBP struggled to meet detention standards. Specifically, several Border Patrol stations we visited exceeded their maximum capacity. Although Border Patrol established temporary holding facilities to alleviate overcrowding, it struggled to limit detention to the 72 hours generally permitted, as options for transferring detainees out of CBP custody to long-term facilities were limited. Also, even after deploying medical professionals to more efficiently provide access to medical care, overcrowding made it difficult for the Border Patrol to manage contagious illnesses. Finally, in some locations, Border Patrol did not meet certain standards for detainee care, such as offering children access to telephone calls and safeguarding detainee property. In contrast to Border Patrol, which could not control apprehensions, CBP’s ports of entry could limit detainee access, and generally met applicable detention standards. Supplementing a May 2019 Management Alert recommendation, we made two additional recommendations regarding access of unaccompanied alien children to telephones and proper handling of detainee property. CBP concurred with the recommendations.