Is The Post Office Open on Presidents Day?

Is there mail delivery on Presidents day 2011?
And will the post office be open on this holiday?
Just wondering if the mail will come today because its a holiday and I'm expecting an important package.
I've been told some mail delivery is active, is it true?

Presidents' Day is a Federal and State holiday. The postal services is a Federal institution so mail won't be delivered in the USA.
Mail carriers are considered government employees, they have the day off.

All federal, state, and local government business offices will remain closed, as will banks, the post office, and other government regulated businesses.
I think that only 24 hour post offices located by major airports are open because they never close.