The writer isn’t addressing a letter here. The use of “Ill.” is suggested by a style manual.
“The writer isn’t addressing a letter here. The use of “Ill.” is suggested by a style manual.”
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I hate style manuals - that’s where we get such nonsense as “undocumented migrants” instead of the common sense, correct term, “illegal aliens”.
As for as the USPS usage nothing is mandatory, I believe. It’s more like - if you want your mail to go faster, use the prescribed method abbreviation and zip code.
I’m a bit old school; I like the fully written out state name, along with zip code usage.