Objectives. Project Northland is an efficacy trial with the goal of preventing or reducing alcohol use among young adolescents by using a multilevel, communitywide approach. Methods. Conducted in 24 school districts and adjacent communities in northeastern Minnesota since 1991, the intervention targets the class of 1998 (sixth-grade students in 1991) and has been implemented for 3 school years (1991 to 1994). The intervention consists of social-behavioral curricula in schools, peer leadership, parental involvement/education, and communitywide task force activities. Annual surveys of the class of 1998 measure alcohol use, tobacco use, and psychosocial factors. Results. At the end of 3 years, students in the intervention school districts report less onset and prevalence of alcohol use than students in the reference districts. The differences were particularly notable among those who were nonusers at baseline. Conclusions. The results of Project Northland suggest that multilevel, targeted prevention programs for young adolescents are effective in reducing alcohol use.