A Postal Mystery

On Saturday the L.A. Times had an interesting article about the Seventh Day Adventist influence in the City of Loma Linda. Buried in the article is this little gem:

Loma Linda is one of a handful of places across the country where mail is delivered Sunday, and not Saturday, in keeping with the Adventists' Sabbath and by arrangement with the Postal Service.

How can you leave me hanging like that? Where are the rest of these "handful" of places? Are they Adventist? Jewish? Is there some other reason? I searched the web last night for an answer, but all was fruitless. Can someone help me out here?

I did come across an interesting history/propaganda article article explaining how the post office used to be open on Sundays, and opining that a lack of Sunday mail service violates the separation of church and state. Man, some people will complain about anything.