State, county, ZIP code, tract and block group: which one should you pick?
A level is the size of the pieces your map is cut into. Smaller pieces show more detail, but need more detailed data. The levels below run from biggest to smallest. All of the outlines come from the U.S. Census Bureau.
State
Fifty-plus big pieces. Good for an online store or anyone who ships across the country.
County
About 3,100 pieces. Good for a service business that covers a region, like a plumber, a roofer or a delivery route.
ZIP code
About 33,000 pieces. The everyday choice for a shop, a restaurant, a gym or a clinic. Most customer lists already have a ZIP code. One note: the Census Bureau draws ZIP code areas a little differently from the Post Office, and a ZIP code that is only a set of P.O. boxes has no area on the map.
Census tract
About 85,000 pieces, each home to roughly 1,200 to 8,000 people. Tracts are small neighborhoods. Use them when a ZIP code is too big to be useful, like in a city.
Block group
About 240,000 pieces, usually 600 to 3,000 people. The smallest level we draw, a few city blocks. Use it for a trade area around one location.
Which should I pick?
- Your list has ZIP codes: pick ZIP code.
- Your list has street addresses or latitude and longitude: pick Census tract or Block group.
- You want the big picture of one region: pick County.
Not sure? Try a few. Each one takes a second.