Food Deserts in the United States
I jokingly call my neighborhood a Food Desert, as there's not a grocery store to be found nearby (and I live in a city!). This piqued my curiosity, and found that there's actually a fairly detailed data set maintained by the Economic Research Service (ERS) and U.S. Department of Agriculture (USDA).
What is a Food Desert?
The USDA defines living in a food desert as:
living more than one mile from a supermarket in urban/suburban areas, and more than 10 miles from a supermarket in rural areas
This data is pulled from the Food Access Research Atlas, and contains information on supermarket access at various distances. This data measures access by the Census-Tract, and as such provides a fairly granular overview. Additionally, what I thought was interesting is that it combined Food Access data with other fields such as age, race, rural or urban, and income.