How long does it take Uncle Sam to cash a fat check?

[sistawendy]

I know the answer to the question in the subject: no more than two days, and possibly only one. The accounts receivable department, or whatever it's called, of the IRS must be the most efficient organization in the entire US government.

I mailed a four-figure back tax payment on the 7th to Ogden, UT via the usual first class mail. It was cashed on the 11th. There's no way it took fewer than two days to get there.