In 2009, Mexico decriminalized the possession of small amounts of illicit drugs for personal use in order to refocus law enforcement resources on drug dealers and traffickers. This study examines the spatial distribution of law enforcement encounters reported by people who inject drugs (PWID) in Tijuana, Mexico to identify concentrated areas of policing activity after implementation of the new drug policy. Mapping the physical location of law enforcement encounters provided by PWID (n = 461) recruited through targeted sampling, we identified hotspots of extra-judicial encounters (e.g., physical/sexual abuse, syringe confiscation, and money extortion by law enforcement) and routine authorized encounters (e.g., being arrested or stopped but not arrested) using point density maps and the Getis-Ord Gi* statistic calculated at the neighborhood-level. Approximately half of the participants encountered law enforcement more than once in a calendar year and nearly one third of these encounters did not result in arrest but involved harassment or abuse by law enforcement. Statistically significant hotspots of law enforcement encounters were identified in a limited number of neighborhoods located in areas with known drug markets. At the local-level, law enforcement activities continue to target drug users despite a national drug policy that emphasizes drug treatment diversion rather than punitive enforcement. There is a need for law enforcement training and improved monitoring of policing tactics to better align policing with public health goals.