"These enterprises have spread throughout the nation in major cities such as Boston, Chicago, Los Angeles and Philadelphia, according to the feds. Los Angeles is a key strategic hub to facilitate the movement of drugs north and west, according to the DEA report, and the city is also used for the “subsequent smuggling of drug proceeds in the form of bulk cash back to Mexico"

"It appears that this will not change in the near future. The DEA, which functions under the Department of Justice (DOJ), predicts that “Mexican TCOs will continue to dominate the trafficking of heroin, methamphetamine, cocaine, and marijuana throughout the United States.” Here’s why: “There are no other organizations at this time with the infrastructure and power to challenge Mexican TCOs for control of the US drug market,” the DEA claims. “Mexican TCOs will continue to serve primarily as wholesale suppliers of drugs to the United States to distance themselves from US law enforcement. Mexican TCOs will continue to rely on US-based gangs to distribute drugs at the retail level"

So yes the Mexican TCO overwhelmingly dominate the distribution and whole sale of drugs in the U.S. The U.S gangs just redistribute to retail.