Drug trafficking networks are an international phenomenon, but much of the discussion about such networks tends to focus on how they are structured and operate in other countries, like Mexico and Colombia. Except for mostly local crime analysis, there is relatively little scholarly research available on drug trafficking on the U.S. side of the border. As a result, there is a significant gap in our understanding of the structure of illicit drug distribution once the product is out of the hands of foreign drug trafficking organizations. This summer, I worked with McNair Scholar Haydee Rojas to develop a research paper that provides a more complete picture of how illicit drugs are distributed in the United States, from wholesale distribution to the consumer market. Identifying the different factors that shape distribution —nature of product, barriers to entry, degree of law enforcement—this paper examines the business operations used to distribute marijuana, cocaine, heroin, and methamphetamine. Using interviews, government and media reports, case studies, and other qualitative field research, the paper finds that these factors significantly shape the business models for the distribution of the major illicit psychotropic substances consumed in the U.S. market. These findings provide a more complete picture of international drug trafficking and organized crime networks, and fill an important void in current policy debates about counter-drug strategy. We plan to present this paper at a Justice in Mexico conference in December 2013.