Are There Any 'Impossible' Series In US Coins?

OK keeping it to just actually made for circulation the stopper is probably the large diameter capped bust half eagle. It's a short set, only made from 1813 to 1829. Ignoring varieties (So you don't need the 1828/7 with only 5 known, or the 1825/4 with only 2 known) there are only 13 coins in the set and every one of them was made for circulation. But you still need the 1815 and there are only 4 known ( RedBook says 4, Coinfacts lists 11, but it looks like so of the pedigrees may be questionable and it could be a few as 7. At least five appearances on the market in be last twenty years though.) Then there is the real stopper the 1822, only three known and two of those permanently impounded in the Smithsonian The other has been off the market for almost thirty years. I don't know who owns the third one. Bass didn't buy the Eliasberg coin when it sold in 82. But that is probably about the closest you're going to get to an impossible set.

It is pretty tough to come across an 1854-S Quarter Eagle unless your family just happens to have descended from a Chinese laborer who saved his first Gold Rush wage. It had a microscopic official mintage of 246 with around 10 known survivors.

Shield nickels 1868 Obv hub A Rev Hub IIC and 1870 Obv Hub A Rev Hub IIA

Tell that to Whitman. At one time they were making Folders with a slot for those.
So far no one has mentioned the 1974 Aluminum Cent. Anyone have a roll of those?
The original post about a completed set is all in what someone wants to say is complete. If all the error and varieties are to be included, then that would possibly be the inpossible one. Since no one really knows how many different varieties of errors and types really exist.
And we all are just going by reports written by different people and again, they too don't know what the Mint may or may not have actually produced. For all anyone knows there may have been many, many coins made for a series, not put into circulation, so are they real or what?

I'm surprised nobody's mentioned the 1943-S copper cent. Only 2 specimens are known so far, if I'm not mistaken.

Maybe this thread should be about ridiculously rare coins instead of those that are literally impossible to obtain like the original post said.

Maybee we should pull together toform the "Impossible series in US coins fund" to buy them lol

And yet I've got an entire roll of those.


AND if you want to include all the different types of platings on those 43 Cents, that alone could start a whole new series. Naturally that would have to include the 44, 44D, 44S Steel if they exist.
The problem with those types are they should not ever be considered part of a real series. If they were, then someone would have to find out exactly how many other mistakes the Mint has made and include those too.
I just think a completed series is one of each type made as real coins. Not errors, not varieties, not possible ones we don't know about, etc.

Somewhere I saw (and downloaded just for fun) the "millionaire's checklist" for US cents, I believe it was.

It's neat to have a list of these rare things, even if owning them is impossible!