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Trade Area · 5 min read

1, 3 or 5 Miles? How a Trade Radius Changes the Picture in 25 US Downtowns

Published October 10, 2026 by the Demografics team

Choosing a trade radius is one of the first decisions in any site analysis, and it is often made by habit: 1 mile for a coffee shop, 3 miles for a grocery store, 5 miles for a big-box retailer. This study shows how much the answer changes with that choice, using the same starting point (City Hall) in 25 major US cities.

Area grows with the square of the radius, so a 5-mile circle covers 25 times the area of a 1-mile circle. Population does not always follow. Going from 1 to 5 miles multiplies the resident population by 36.8 times in Phoenix, AZ but only 6.4 times in San Francisco, CA, depending on whether the core is already dense or the dense neighborhoods sit further out.

How we measured

For each city we drew 1-, 3- and 5-mile circles around City Hall and combined ACS 2018–2022 data for the census tracts inside each circle. Each downtown is measured from City Hall at its street address. Miami is measured from the Stephen P. Clark Government Center (111 NW 1st St) because Miami City Hall sits in Coconut Grove, outside the downtown core. Trade-area figures combine every 2020 census tract whose internal point lies inside the radius. Counts are summed; the median household income and median age of an area are household- and population-weighted averages of the tract medians, a standard approximation. ACS figures are survey estimates with margins of error, so small differences between places should not be over-read.

Population by radius

Median household income by radius

In 9 cities the 5-mile median income is more than 10% higher than the 1-mile figure (Atlanta, Phoenix, San Francisco, Seattle, San Antonio, Portland, Los Angeles, Riverside and Denver): the immediate core is less affluent than the surrounding neighborhoods. In 8 cities it is more than 10% lower (New York, Philadelphia, Boston, Detroit, Orlando, Charlotte, Chicago and Miami): an affluent core gives way to lower-income neighborhoods further out. A store targeting a particular income band can therefore look like a good or bad fit purely because of the radius chosen.

Density and age change with distance

In 23 of the 25 cities the 1-mile circle is denser than the 5-mile circle, the classic pattern of a dense core. In the other 2 (Phoenix and San Antonio), the densest neighborhoods are further out than the immediate downtown, often because the core is dominated by offices, government buildings or water. Median age rises by more than two years between the 1-mile and 5-mile circles in 10 cities.

How to choose a radius

• Start from how customers travel. Walk-in and transit-heavy concepts usually draw from a much smaller area than drive-to destinations.
• Look at all three radii, not one. If the numbers change sharply between 1 and 3 miles, small differences in the exact site can matter a lot.
• Watch for edges. Water, freeways, rail yards and parks reduce the real catchment; circles do not know about them.
• Use the same radius when comparing sites, or the comparison will mostly measure the radius.

Sources

• U.S. Census Bureau, American Community Survey 5-year estimates, 2018–2022 (tables B01001, B01002, B01003, B11001, B19001, B19013, B25003, C24050).
• U.S. Census Bureau, TIGERweb 2020 census tract boundaries (used to find the tracts inside each trade radius).

More data studies

• Who Lives Within 3 Miles of Downtown? Census Profiles of 25 Major US Cities
• Is Downtown Richer or Poorer Than the Metro? Income in 25 US Cities Compared
• Where Young Adults Live: The 18–34 Share in the 50 Largest US Metros and 25 Downtowns
• Renters vs Owners: Housing Tenure in the 50 Largest US Metros and Their Downtowns