[ericvsmith]

That’s actually the Bureau of Engraving and Printing, on 14th St. SW, which is indeed worth visiting. They print the paper bills (among other things). The U.S. Mint produces the coins. I think only the Philadelphia Mint still mints coins, but it’s also worth visiting.

[dhosek]

Denver also mints coins for circulation (mint mark D) and San Francisco does rarely, but mostly does proof sets (legal tender, but generally kept by collectors). Apparently there’s also a newer mint at West Point which uses a W mint mark and also mints coins for circulation.