This is an amazing story. I don’t live on campus, but when I did the mail system was a constant anxiety.

AU’s mail system is a walled garden; letters are passed through a central mail room before delivery to their building. It just isn’t designed for geographic accuracy. A district splitting the campus and its one mailing address in half probably was not a planned edge-case.

My hypothesis is that the Board of Elections’ system saw:

4400 Massachusetts Ave NW
Letts Hall 100
Washington, DC 20016

as the same as

4400 Massachusetts Ave NW
Washington, DC 20016

If this is true, I’m not sure if it happened at the time of registration or when the ballot was requested.

The USPS has some awareness of the campus mailing system. Searching the ZIP Code Lookup Tool for “Centennial Hall 400” with AU’s 5 digit ZIP code resolves to a mailable address.