10.7910/DVN/WDS8HBEsberg, JaneJaneEsbergUniversity of PennsylvaniaHarvard Dataverse2025Social SciencesEsberg, JaneJaneEsbergUniversity of PennsylvaniaEnter your name here: LastName, FirstNameFirstNameEnter your name here: LastName2025-01-132025-01-14435580038195122729246857396011295983994223863213031001025020461116591text/tab-separated-valuestype/x-r-syntaxtext/plainapplication/pdftext/tab-separated-valuestext/tab-separated-valuesapplication/zipped-shapefiletext/tab-separated-valuestext/plainapplication/octet-streamtext/tab-separated-valuestext/tab-separated-values1.0CC0 1.0Mexico’s war on drugs is increasingly characterized by small, local groups rather than large cartels. This research note introduces new data developed from a narcoblog – a citizen journalism website – on more than 450 criminal organizations operating in Mexico between 2009 and 2020. I use the data to test prominent theories of fragmentation, providing suggestive evidence that drug war policies contributed to a more complex conflict: kingpin removals were correlated with the emergence of smaller groups; profit opportunities (here fuel theft) then attracted these organizations to new territories. This research contributes to our understanding of criminal control and informs debates over policies aimed at violence reduction.