USPS Workers - Explain to me how Illinois zip codes start with a 6

[momeNt]

Despite being EAST of 5 prefix zip codes.

Neighboring state is Indiana (4) to the east, and Iowa (5) to the west.

This makes no sense. Unable to find anything about it at the internet. I can't be the first to realize the east to west convention of 0 thru 9 missed Illinois?

 

[herm0016]

and wyoming is 8 and montana 5. never thought about it.

 

[dullard]

https://www.mapsofworld.com/usa/zipcodes/images/usa-zip-code-map.jpg

Looks like they went right-to-left and top-to-bottom. Seems reasonable considering that we were settled by Europeans first in the top right. Or the original zip code maker spoke one of the Right to Left languages. https://en.wikipedia.org/wiki/Right-to-left

 

[nakedfrog]

Hm, interesting. The 5xx kinda wraps around it.
http://mapshop.com/media/wall/territory/3digitzipus.jpg

 

[momeNt]

and wyoming is 8 and montana 5. never thought about it.

Wow @ Montana being a 5.

That one is truly inexplicable.

 

[Thebobo]

Wow @ Montana being a 5.

That one is truly inexplicable.

I would give Montana a 10

 

[who?]

Illinois is next to Missouri which is also a six.