Chicago

IllinoisUnited States

With a code: #G2678-5976G
Said aloud: Chicago 5976G

What the code says

The Grid Point Code for Chicago is #G2678-5976G. It names a cell 2.56 m north to south and 2.55 m east to west, centred on 41°51'00.10"N, 87°39'00.15"W, and it turns back into that cell on any phone or computer by arithmetic alone: no network, no account, no lookup table.

The point used is the one GeoNames records for Chicago, near its centre.

Code: #G2678-5976G
With a check character: #G2678-5976G*N
Short form: 5976G
Cell centre: 41.850029, -87.650043
Cell size: 2.56 m by 2.55 m
Region: Illinois
Country: United States
Population: 2,664,452

How to give this address

On a sign, a form or a delivery note: The whole code, #G2678-5976G. It needs nothing else: no city, no street, no network to read it back.
Said aloud, in Illinois: Chicago 5976G: a name both people know, then the last five characters. They give back the exact code for anywhere within 4.0 km north or south and 4.0 km east or west of Chicago. Further away the same five name somewhere else, which is why the whole code is what goes on a sign.
Copied by hand, or read over a phone: #G2678-5976G*N. The character on the end catches any single mistyped symbol and any two neighbours swapped.
As a link or a square code: Open it on the map, move to the exact door, and add directions if the code needs help: "blue gate, second floor". The link and the square code carry them. Nothing is kept on this site.

From the city to the door

The first four characters name a cell about 40 km by 39.8 km here. Each one after that picks one of 25 inside the last, so the whole ten name a spot about the size of a doorway.

G267Metropolitan area40 km by 39.8 km
G2678District8 km by 7.96 km
G26785Suburb1.6 km by 1.59 km
G267859A few streets320 m by 318 m
G2678597Building64 m by 63.7 m
G26785976Entrance12.8 m by 12.7 m
G26785976GDoorway2.56 m by 2.55 m

More in United States

City, region and population from GeoNames, under CC BY 4.0.