USDA Introduces Online Tool for Locating 'Food Deserts' in USA

By Susan Jones | May 3, 2011 | 9:31 AM EDT

Fruit waiting to be sold at a farmers' market in Baltimore. (AP Photo/Steve Ruark)

( - The U.S. Agriculture Department on Monday introduced an online "Food Desert Locator," showing where in the United States residents have limited access to affordable and nutritious foods. 

The Obama administration defines a food desert as a low-income census tract where either a substantial number or percentage of residents lacks easy access to a supermarket or large grocery store. (The Census Bureau defines a census tract as a small, relatively permanent statistical subdivision of a county.)

The USDA says its new online tool can be used to expand the availability of nutritious food in low-income communities. The agency also noted that expanding the availability of nutritious food is part of First Lady Michele Obama's campaign against childhood obesity.

"This new Food Desert Locator will help policy makers, community planners, researchers, and other professionals identify communities where public-private intervention can help make fresh, healthy, and affordable food more readily available to residents," Agriculture Secretary Tom Vilsack said in a news release. "With this and other Web tools, USDA is continuing to support federal government efforts to present complex sets of data in creative, accessible online formats."

For purposes of the Food Desert Locator, "low income" tracts are defined as those where at least 20 percent of families have income at or below the federal poverty level, or where median family income for the tract is at or below 80 percent of the surrounding area's median family income.

Tracts qualify as "low access" if at least 500 persons or 33 percent of the population live more than a mile from a supermarket or large grocery store. For rural census tracts, the distance to a supermarket is set at more than 10 miles. The definitions were developed by a working group comprised of staffers from the departments of Treasury, Health and Human Services, and USDA, which is partnering to expand the availability of nutritious food.

Under these income and food-access criteria, about 10 percent of the 65,000 census tracts in the United States meet the definition of a food desert, the USDA said. These food desert tracts contain 13.5 million people with low access to sources of healthful food. The majority of this population — 82 percent — live in urban areas.

Users of the Web-based Food Desert Locator can view and download statistics on the population characteristics of a selected tract, such as the percentage and number of low-income people who have low access to large grocery outlets, or the number of "low-access" households without a car.

For example, in Cook County, Ill., which includes Chicago, 39 census tracts are identified as food deserts. These tracts contain more than 81,000 people, including more than 26,000 children under the age of 18. The Locator allows users to zoom in and view street names and other features of the food desert census tracts.

Some of the wealthiest counties in the nation, such as Fairfax in Virginia, have food deserts, and so does the neighboring city of Washington, D.C.

An earlier Web mapping tool -- the Food Environment Atlas -- unveiled last year by First Lady Michelle Obama -- presents a broad set of statistics on food choices, health, and community characteristics at the county level.  It does not define or identify food deserts.