The US Bureau of Engraving and Printing has a cute named web site http://www.moneyfactory.gov/

Where you can select US Currency / Production Process to learn the details, they also offer tours in Washington DC and Texas.

Anyone who has collected pennies know they had multiple production facilities designated by a little letter printed under the year. D for Denver, S for San Fransisco and none for Philadelphia.

http://www.usmint.gov/about_the_mint/col...

Is the U.S. Treasury in Washington D.C. Or do they have them in different states?

UK In the Royal Mint

At the U.S. Treasury.