The Affordable Care Act requires the establishment of new health insurance marketplaces -- known as exchanges -- in every state by October 1, 2013. This report examines key design decisions made by the 17 states and the District of Columbia that chose to establish a state-based exchange. The analysis finds that states made significant progress in structuring their exchanges, with states varying in their design decisions. Many states expect to exceed some federal requirements -- to collect and display quality data, for instance -- for 2014. These findings suggest that states capitalized on the flexibility provided by the Affordable Care Act to tailor their exchanges to their unique needs and made decisions with an eye towards outcomes, such as enrollment, consumer experience, and sustainability. These findings also suggest that states' initial decisions will inform future exchange implementation and that states will adjust their decisions while continuing to adopt innovative approaches to accomplish policy goals.