This Policy Brief analyzes the 2014 premiums of health insurance plans available in the new marketplaces created by the Affordable Care Act. Using methodology developed in an earlier Policy Brief, we find that initially, a state-based marketplace design and an "MSAs+1" rating area design are associated with lower average premiums. Rating areas with more than 1000 people per square mile also tend to have the lower premiums. We find that the rating areas with the highest average premiums are characterized by smaller populations, greater land areas, and far fewer health providers per square mile.