Hermosillo, Ciudad Obregón, Agua Prieta, Saltillo, Monclova, Ciudad Acuña and Piedras Negras seem to have relatively low levels of violence given their closeness to the U.S. Border. Is it because they are firmly under the control of a single drug cartel? The drug-related homicide rates for Tijuana and Mexicali are likely underestimated in this dataset given their high homicide rates.
Since the drug related homicide data was only released at the municipality level, I calculated the centroids of the municipalities taking the population weighted means of the latitude and longitude of the localities within each municipality based on the 2000 census.
These maps give a good idea of what has been happening in Mexico during the last few years:
In 2009 Michoacán once more turned violent and the federal government again sent troops to pacify the region. A the end of the year the brother of “El Mochomo” was killed in Cuernavaca and this sparked a surge in violence in Sinaloa and Guerrero as the Sinaloa Cartel tried to destroy the remains of his organization once and for all. In 2010 the Gulf Cartel went to war with the Zetas which is why northeastern Mexico turned red.