Migrant Deaths in California’s Borderlands, 2018–2023
Authors: LaFleur Marni , On Kat , Ceja Ligia , Martínez Daniel E. 
Published: November 2024

Executive Summary We examine the deaths of undocumented migrants in southern California (i.e., San Diego and Imperial counties) for fiscal years (FYs) 2018–2023 using data obtained from the San Diego County Medical Examiner’s Office (SDCMEO) and Imperial County Coroner’s Office (ICCO). We recorded 314 deaths of undocumented migrants, with 157 in San Diego County (SDC) and 157 in Imperial County (IC). We describe trend fluctuations in migrant deaths and both the overall and county-specific proportions as they relate to causes of death and demographic characteristics (biological sex and age at death). Additionally, to capture the potential effects of the 2019 border wall expansion and COVID-19 pandemic on migrant deaths, we examined differences in these factors between two periods: FY 2018–2019 and FY 2020–2023. We conclude by comparing migrant deaths reported by the medicolegal authorities to estimates published by US Customs and Border Protection’s (CBP) Border Patrol for southern California. From 2018 to 2020, there were approximately 30 known migrant fatalities annually in California. This increased to about 88 deaths per year in 2021 and 2022 before dropping to 50 in 2023. Across the study period, the leading causes of death were drowning (35.4 percent), environmental exposure (23.6 percent), and blunt force trauma (16.9 percent), with the latter cause being largely associated with falls from the border wall. However, we found significant differences between SDC and IC. For instance, 51.6 percent of migrant deaths in IC were due to drowning, compared to 19.1 percent in SDC. Conversely, 21.7 percent of deaths in SDC were due to blunt force trauma, while just 12.1 percent of deaths in IC occurred in this manner. Overall, we found that 75.2 percent of decedents were male, 20.4 percent were female, and 4.5 percent were of unknown sex. Among cases in which a precise age at death was listed, the average age was 34.6 years. Nevertheless, sex and age differed by county in that SDC had a higher proportion of female decedents (28 percent in SDC vs. 12.7 percent in IC) and a higher average age at death (SDC x¯ = 36.8 vs. IC x¯ = 32.0). We also found significant differences between the two periods examined. Perhaps most striking, deaths due to blunt force trauma increased from 3.4 percent of cases in FY 2018–2019 to 19.9 percent of cases in FY 2020–2023. Decedent characteristics also appear to have changed across time. The share of male decedents decreased from 84.5 percent to 73.0 percent, while the share of females increased from 5.2 percent to 23.8 percent between the two periods, while the proportion of decedents ages 50 to 64 years increased significantly (from 4.7 percent to 12.7 percent). Finally, for FYs 2018–2022, CBP reported 25.6 percent fewer migrant deaths than medicolegal authorities in southern California. High numbers of migrant deaths in 2021 and 2022 can be attributed to circumstances during and following the COVID-19 pandemic, including a Trump Administration policy aimed at blocking access to the US asylum system. The expansion of the border wall during the Trump era may also explain increased migrant mortality in 2021 and 2022. Decreases in deaths in California in 2023 may be because of a novel entry location in the San Judas Break or result from a shift in migration trends toward other border states (i.e., Arizona, New Mexico, and Texas). County differences in drowning and blunt force trauma deaths were likely due to the presence of the All-American Canal in IC (drowning), and greater coverage of the pedestrian border wall in SDC (blunt force trauma), respectively. Although speculatory, the higher percentage of female decedents and older age of decedents in SDC may be because these vulnerable individuals perceive San Diego to be a safer route. Changes between FYs 2018–2019 and FYs 2020–2023 in blunt force trauma deaths (3.4 percent to 19.9 percent) are a result of falls from the newly expanded and constructed border wall. We suggest that after more than 30 years of implementation, the United States should eliminate the use of “deterrence” strategies to prevent further and unnecessary loss of life. Additionally, the following actions could reduce migrant mortality in California: installing buoys or other anti-drowning devices in the All-American Canal, making potentially life-saving resources (e.g., blankets and water) available on known migrant routes, and reducing the height of or removing the border barrier. We call for both CBP and medicolegal authorities to provide disaggregated data on migrant fatalities, which would facilitate an accurate accounting these deaths, increase understanding of where and why deaths occur, and therefore be used to support policy changes.