Food access among low-income populations has long been a concern in the United States. Recent research on the geographic dimensions of access has focused on economically deprived areas with little retail food activity, referred to as' food deserts.'We illustrate concepts of urban food access in this descriptive case study from post-Katrina New Orleans. We augment conventional definitions of food deserts by considering a variety of retail food outlets from a complete mapping of the city and by incorporating data on in-store contents on availability and shelf space of fruits and vegetables from a stratified sample of outlets. We show that the existence of food deserts depends on the definitions employed; commonly-used constructs in the food desert literature result in prevalence rates for New Orleans of anywhere from 17% to 87% of the city's 175 census tracts. Ambiguities inherent in the construct do not diminish the fact that long travel distances to procure food do increase at-home food costs and that contextual effects on individual health and community development are often associated with areas of impoverished food resources. Describing poor geographic access can improve assessments of household resource inadequacy; we illustrate how transport costs can be used to inform federal food assistance policy. We also show how identifying areas of need can be used at the local level to prioritize retail food projects. Given the current problems of over-nutrition, the paper concludes by suggesting a more useful geographic metaphor would be “food swamps,” areas in which large relative amounts of energy-dense snack foods, inundate healthy food options.