American Indian and Alaska Native (AIAN) populations have about twice the rate of nutrition-related health conditions, including cardiovascular disease, diabetes, and obesity, as non-Hispanic White Americans. The authors found likely sources of healthful, afford-able food to be limited in many tribal areas, a factor that may influence diet and food choices. Access to large grocery stores and supermarkets-which sell food needed for a healthy diet-varied by tribal area. AIAN tribal area populations are mostly rural, unlike the national population. Spatial analysis revealed that 25.6 percent of individuals living in tribal areas were within 1 mile of a supermarket-defined as walking distance-compared with 58.8 percent of all Americans. The largest share of AIAN tribal area populations are between 1 and 10 miles from a supermarket, defined as driving distance. Among the 6 percent of tribal area households without vehicles, more than two-thirds lived more than 1 mile from the nearest supermarket. Measures of access are also reported for supermarkets authorized for the Supplemental Nutrition Assistance Program and outlets used by the Food Distribution Program on Indian Reservations.