The battle for control of lucrative smuggling routes into the United States has left several Mexican border cities with some of the highest homicide rates in the world. But the violence has generally stayed south. In 2010 the average homicide rate in all U.S. border cities was actually lower than the U.S. national average.
In 2011, nearly 40 percent of migrant arrests occured in Tucson sector, one of nine divisions that make up the U.S. Border Patrol in the Southwest.
Two decades ago, about 3,500 U.S. agents monitored the entire border; last year, more than 18,000 did. More than 4,000 monitored Tucson sector in 2011.
Border sectors in Arizona, Southern Califorina and southeast Texas accounted for the most arrests per agent in 2011.
The greater number of Border Patrol agents has not slowed the amount of illegal drugs flowing into Southwest-sector states,
and the increase in drug seizures could indicate a rise in attempts to smuggle drugs across the border.
A drug war between the Sinaloa and Juarez cartels turned some Mexico border cities into the most dangerous places in the world. In 2010, during the peak of the violence, the high murder rates stayed south — the average homicide rate in all U.S. border cities was lower than the U.S. national average in 2010.