During 2002-2004, 8.1 percent of individuals in the United States aged 12 or older had used an illicit drug in the past month. West Kansas and Utah County, UT, reported the lowest rate at 5.0 percent; the highest rate (13.6 percent) was reported by northern California. The highest 15 areas were dispersed among 10 States. Marijuana was the most commonly used illicit drug, and many of the areas with a high rate of illicit drug use reported high rates of marijuana use. Other illicit drugs used included cocaine/crack, heroin, hallucinogens, inhalants, or any prescription-type psychotherapeutic drug used nonmedically. Past-month use of these substances ranged from a low of 2.6 percent in Montgomery County, MD, to a high of 5.1 percent in the Bluegrass, Comprehend, and North Key region of Kentucky. Alcohol was the most commonly used substance, with 50.4 percent of respondents reporting past-month use of alcohol. Binge alcohol use was reported by 22.8 percent of respondents. Approximately 30 percent of respondents used tobacco in the past month. The national rate for past-year dependence on or abuse of alcohol or illicit drugs among respondents was 9.3 percent. Substate areas were defined by officials from each State and the District of Columbia typically based on the substance abuse treatment planning areas specified by the States in their applications for the Substance Abuse Prevention and Treatment Block Grant administered by the Federal Substance Abuse and Mental Health Services Administration. Extensive tables and figures