[show abstract][hide abstract] ABSTRACT: The aim of this research was to explore the increasingly popular Dutch health phenomenon of 'gathering in private peer group settings (barracks)', with a focus on the prevalence and characteristics of barracks, alcohol consumption, and other (risk) behaviors of their visitors. Three studies were conducted. The first consisted of field research in which 51 barracks were visited and group-interviews were held. The second was an Internet study in which 442 barracks' websites were analyzed using content analysis. The third consisted of a questionnaire completed by 1457 adolescents, aged 15-17, in order to explore differences in behavior between barracks visitors and non-visitors. There was wide variation in barracks' characteristics and culture. Barracks' members and visitors also organize diverse activities that are publicly shown on the websites. Barracks are associated with various legal issues, such as alcohol sales to minors, lack of parental supervision, and illicit drug use. Barracks' visitors drink alcohol more frequently, drink more alcohol per occasion (up to fifteen bottles of beer a night), and have been drunk more frequently than non-visitors. Policymakers must be aware of the barracks phenomenon and use their powers in adjacent political and legal areas (such as in binge drinking, illicit drug use, and public safety) to intervene and create solid, responsible, and tailor-made policies.