Walk Score has a tool to generate heat maps showing how far you have to walk to reach things like a grocery store. Here’s DC’s grocery access map:
According to the Walk Score blog, 41% of DC residents are within a 5-minute walk of a food store, placing it 5th among US cities of half a million residents or more and just below Boston (45%). New York is tops, at 72%.
DC’s sustainability plan (which gets a special mention in the WalkScore post) calls for 75% of people to have a food store within a 5-minute walk by 2032.
Southern and southwestern cities rank the worst, with Indianapolis, Oklahoma City, Charlotte, Tucson and Albuquerque all or at or below 7%. Tucson is an interesting case in that the city has done a lot to make it safer to walk, such as adding pedestrian signals to help people cross its wide streets, but everything is very spread out making many walks quite long.