Hospital use and hospital mortality related to firearm-assault injuries varies considerably across demographic groups and states, as does the percentage of firearm-assault injury hospital costs borne by the public. Healthcare data from six states--Arizona, California, Maryland, New Jersey, North Carolina, and Wisconsin--show that hospital use for firearm-assault injury is disproportionately concentrated among young males, particularly young black males. Additionally, uninsured victims have higher hospital mortality rates for firearm-assault injury. Across all six states, the public pays a substantial portion of the hospital cost for injuries caused by firearm assault.