At the end of 2011, the drug trafficking cartels Zetas and the Sinaloa cartel firmly established themselves as the two largest and strongest drug cartels in Mexico.
According to law enforcement officials, the Zetas were operating and in control of 17 states and federal districts throughout Mexico, while the Sinaloa cartel was operating in 16 in 2011.
Back in 2007, the Sinaloa cartel was in 23 states and federal districts.
Source: Geoffrey Ramsey, “Have the Zetas Replaced the Sinaloa as Mexico’s Most Powerful Cartel? ,” Insight Crime, January 3, 2012.