The Arizona HIDTA includes eight western and southern counties in the State, including counties along the State's entire U.S.-Mexican border. Mexican drug trafficking organizations (DTOs) that smuggle marijuana across the U.S.-Mexico border in Arizona are an increasing threat to the region; the Arizona border area is the principal U.S. arrival zone for Mexican marijuana. The availability of cocaine and ice methamphetamine decreased throughout the region in 2008, partly due to increased Mexican law enforcement and military targeting of Mexican DTO activity. The amount of heroin seized in the region increased significantly in 2008, partly due to a decrease in aerial eradication of the opium poppy plantations in Mexico and the increase in violence along the primary smuggling corridors into the United States. Mexican DTOs are now using routes that lead into Arizona HIDTA counties or transit the area en route to Mexico. Mexican DTOs are using underground tunnels to smuggle illicit drugs from Mexico into Arizona. Mexican DTOs that operate in Mexico and Arizona often use violence, corruption, and intimidation to maintain their cross-border smuggling routes. Methamphetamine abuse poses the most serious drug-related concern to law enforcement officials throughout Arizona because of the drug's widespread availability, highly addictive features, its association with violence, and apparent appeal to youth. More detailed information is provided on Phoenix and Tucson market areas. 8 tables, 2 figures, and a listing of data sources for this report