The HOPE model is a detailed, dynamic compartmental model of HIV disease progression and transmission in the United States. We parametrized and calibrated the model to closely match the population of people living with HIV between 2006 and 2010, to project HIV transmission into the future. The population was stratified by age, sex, circumcision status, race/ethnicity, transmission group, and risk level. Outcomes included HIV incidence, prevalence, and care status. We employed the HOPE model to evaluate the cost-effectiveness of HIV interventions and explore HIV prevention policy questions.