Comment by joegahona

> I’m pretty sure that’s not because New York is a proper noun, but because it is an open compound.

You are correct -- it's not because it's a proper noun. The rule I recall is that if a proper noun is also a compound modifier, the en dash is warranted. (I think this is in Chicago.) The example you gave from Chicago's FAQ is sort of the same rule but with the en dash coming at the beginning.

And the author of the original blog post caveated his use of the en dash (instead of the em dash), which I missed when I read it the first time, and speaks to your point of some style guides calling for an en:

> Choosing between the en dash or em dash is not a big deal. In my writing (as a manager corresponding with government officials and politicians, and also as a marketer communicating with real people) I use ‘space-n-dash-space’ instead of the em-dash – just to keep everyone happy.