The other day, I mailed something for my wife at the SLC airport post office, which is open 24 hours, seven days a week (including holidays). That got me thinking: what other post offices in large cities are open 24 hours? That could be useful information to know if I am in a city and, late at night, suddenly have a need to get something postmarked with the current day's stamp. I don't see where this information is shown on the USPS website, so if anyone out there knows where such a list is posted, please share. Thanks.

BTW, the SLC airport post office is not actually at the passenger terminals. It is instead located within walking distance, about a quarter-mile south of Terminal One, in with all of the air cargo operations. (There is free parking at the post office for those using it.)