A food desert is not an area with no food. It is an area where the affordable food is far away and the near food is expensive, and the federal government measures it by combining two conditions: household income and distance to a supermarket. Roughly 11 to 27 percent of the U.S. population lives in a census tract meeting both, depending on which distance threshold you use.
The range is wide because the definition has four versions. Understanding why matters more than memorizing a single number.
How the government defines it
The USDA Economic Research Service builds its measure from census tracts that are both low-income and low-access.
A tract counts as low-income if its poverty rate is 20 percent or higher, or its median family income is at or below 80 percent of the state or metropolitan area median.
A tract counts as low-access if a significant number or share of residents live far from the nearest supermarket, supercenter, or large grocery store. The Economic Research Service sets that as at least 500 people or at least 33 percent of the tract population living more than half a mile or one mile from a store in urban areas, and more than 10 or 20 miles in rural areas. A fourth measure counts vehicle access directly, flagging tracts with at least 100 housing units lacking a vehicle and located more than half a mile from a store.
Using the one-mile urban and ten-mile rural thresholds, the Economic Research Service identified 7,941 urban and 1,352 rural low-income low-access tracts in 2019, both slightly higher than in 2015. Separately, about 40 percent of the U.S. population lived more than a mile from any food store.
One caveat worth carrying: the underlying retailer data in the agency’s mapping tool still reflects 2019 stores and 2010 tract boundaries, with an update expected in the 2026-27 winter. These are the best federal figures available and they are not current-year.
Why distance turns into cost
A supermarket two miles away is a minor inconvenience with a car and a structural problem without one. Public transit with grocery bags limits how much a person can carry, which forces more frequent, smaller trips. Smaller trips eliminate bulk pricing and raise the per-unit cost of everything.
The substitute is the nearby small store, and it charges more for identical goods. Researchers led by Melissa Laska measured this in the Minneapolis and St. Paul area, publishing in the International Journal of Environmental Research and Public Health in 2017. Matching staple items in small stores against the nearest supermarket carrying the same product, they found every item except white bread cost more at the smaller store, with Cheerios 54 percent higher, bananas 53 percent, and white rice 50 percent.
Older USDA Economic Research Service work found smaller premiums against convenience stores specifically: milk about 5 percent higher, ready-to-eat cereal about 25 percent, and bread about 10 percent. The same agency added a necessary qualification, noting that convenience stores account for only 2 to 3 percent of food spending among low-income consumers.
Both studies are dated, the Laska work covers one metro area, and neither describes today’s prices. They establish that the premium exists, not its current size.
What food costs right now
The USDA Economic Research Service’s Food Price Outlook, updated in August 2026, recorded food-at-home prices up 2.7 percent and food-away-from-home prices up 3.4 percent over the twelve months ending July 2026. It forecasts food at home rising 2.5 percent across 2026 and food away from home 3.6 percent.
Category movement matters more than the average for a household buying staples. The same forecast puts beef and veal up 9.8 percent for 2026, sugar and sweets up 7.1 percent, and fresh vegetables up 5.9 percent, against eggs down 30.8 percent after their earlier spike.
The Bureau of Labor Statistics, measuring the same thing in its August 2026 Consumer Price Index release, put food at home up 2.2 percent over twelve months and food away from home up 3.4 percent.
The benefit does not track the basket
Federal food assistance is calculated from a specific grocery basket, and the timing creates a gap.
The USDA prices the Thrifty Food Plan monthly. In July 2026 it cost $1,024.90 for the reference family of four. The maximum monthly SNAP allotment for a household of four in the 48 contiguous states and the District of Columbia for fiscal year 2026 is $994.
The maximum benefit is set once a year from the June cost of the plan, then held fixed through September of the following year. Food prices keep moving during that window. By July, the government’s own estimate of what the basket costs ran about $31 a month above the maximum benefit designed to buy it.
The benefit is also a maximum. Households with countable income receive less, since the calculation reduces the allotment as income rises.
How many households come up short
The USDA Economic Research Service reported in December 2025, using December 2024 survey data from 32,719 households, that 13.7 percent of U.S. households, about 18.3 million, experienced food insecurity at some point in 2024. Another way to read it: 86.3 percent were food secure all year.
Within that total, 5.4 percent had very low food security, meaning normal eating patterns were disrupted and intake reduced. Among households with children, 9.1 percent reported food insecurity among the children themselves, and 0.9 percent, about 318,000 households, reported very low food security among children.
The 2024 figure is not statistically different from 13.5 percent in 2023 or 12.8 percent in 2022. The problem is stable rather than improving.
What the label gets wrong
“Food desert” suggests absence, and absence suggests the fix is opening a store. Research on new supermarket openings in underserved areas has generally found smaller improvements in diet than the metaphor predicts, because distance is one constraint among several.
A household can live across the street from a supermarket and still not afford what is in it. The USDA’s own definition builds income into the measure precisely because access without purchasing power does not solve anything.
Fight For A Living Wage, a nonpartisan grassroots 501(c)(3), frames food as one piece of an affordability problem that also covers housing, healthcare, childcare, transport and education, arguing that full-time work should cover those basics. The federal food data is consistent with that framing. A benefit running $31 below its own reference basket, a 2.5 percent annual price increase, and beef up nearly 10 percent describe a budget problem that a new grocery store does not fix.
The USDA publishes the Food Access Research Atlas, the Food Price Outlook, the Thrifty Food Plan cost reports, and the household food security series, all free to the public.