Border Crosser Deaths in the Arizona-Mexico Desert: Data on Remains 2001-2020.

Introduction: Increased enforcement at U.S.-Mexico border-crossing sites may lead migrants to cross in remote desert areas.

Methods: We reviewed data on migrants' bodies found along the Arizona-Mexico border from 2001 to 2020. We analyzed causes of death, condition of bodies, age, and sex, and the relationship of deaths to enforcement (arrests) by U.S. Border Patrol.

Results: From 2001-2020, 3,378 border-crosser bodies were found in the desert. As enforcement increased, bodies were found in more remote areas and later stages of decomposition. Skeletonized bodies increased from 19% in 2001-2004 to 49.1% in 2017-2020. When the cause of death could be identified, exposure to the elements was the most common cause. Abrupt increases in arrests and deaths over the immediately preceding period of 2013-2016 occurred in 2017-2020.

Conclusions: Undetermined cause of death and increased skeletonization became more common, indicating bodies are discovered later. Enforcement does not decrease individuals crossing the border; rather, individuals cross in more remote areas.