Lincoln Memorial Cents?
Roosevelt Dimes?
State Quarters?
It depends somewhat on how you define Key.
I am assuming a Key is significantly rarer than the median.
And that the series is just dates and mint marks, not die varieties which can be somewhat rare like the 1c 1972 DDO.
American Innovation Dollars.
All low mintage and NIFC.
Coins are Neato!
"If it's a penny for your thoughts and you put in your two cents worth, then someone...somewhere...is making a penny." - Steven Wright
"Key" is a relative term. Most modern series could cite the 1981-S Type 2 as a key for example
Custom album maker and numismatic photographer.
Need a personalized album made? Design it on the website below and I'll build it for you. https://www.donahuenumismatics.com/.
The concept of "key" is better viewed as marketing. Any series can be considered to include "keys" if the definition is narrow enough. Now, it just seems to be which ones are the most expensive, as outside of legitimately (somewhat) difficult to buy coins, all others can be bought in a quality collectors traditionally accepted at any time or short notice.
Another way of looking at it is how many US series can be completed in high quality (subjectively in an MS holder from any leading TPG) in one day. I've looked intermittently on eBay and Collector's Corner and the list sure isn't short. It includes series most US collectors consider scarce.
I consider the most relevant usage of "key" to be the one I infer was used for 60's US circulating designs. This includes wheat cents, Buffalo nickels, Mercury dimes, SLQ, and WLH. To this I'd add the Morgan and Peace dollar, IHC, Barber series, and the Indian Head quarter eagle.
I have watched the 1949-PDS Franklins move from #1 to #3 over the years. I paid way too much for a 1949-S when it was hot. The 1949-D was last then. It became #1 later. It changes too much for me to care.
Retired dealer and avid collector of U.S. type coins, 19th century presidential campaign medalets and selected medals. In recent years I have been working on a set of British coins - at least one coin from each king or queen who issued pieces that are collectible. I am also collecting at least one coin for each Roman emperor from Julius Caesar to ... ?
A date and mint mark set of Barber half dollars basically has no keys. However a nice collectible 74 coin set in G4 would run about $5500 according to the PCGS price guide.
I have watched the 1949-PDS Franklins move from #1 to #3 over the years. I paid way too much for a 1949-S when it was hot. The 1949-D was last then. It became #1 later. It changes too much for me to care.
I was going to buy a 1949-S FBL in 65 or 66 but, when I saw a 66 (without FBL designation), in a PCGS/CAC holder, I jumped at it. It has nice original toning. The 1949-S was always considered the key (for non-FBL coins), as long as I can remember. I'll buy FBLs, when possible, but they aren't an important criteria for me, as I simply don't care that much. The 1953-S is the perfect example. A 65 FBL is $32K and even a 64 FBL is $20K. That's nuts. With enough searching you can find a plain one that is close without the HUGE premium.
Sometimes, it’s better to be LUCKY than good. 🍀 🍺👍
What about the gold Presidental Spouse series? No real keys, even if you look at the low mintages of the last few years, but expensive as bullion has placed them around $2500. melt.
@ambro51 said:
No keys. No 1885 v Nick. No VDB MPL. Etc….
Most were not keys ‘til the collecting public could not find them in circulation anymore. Or, until
they were discovered as a variety or error that was generally accepted into sets. (3-legged Buffalo, overdates, doubled dies or low mintage numbers; as examples ). There just aren’t enough 1914-D Lincoln cents for every cent collector. But it’s the 1909-S VDB we call “the key”. Some think the high and low leaf Wisconsin 2004-D SHQ was a concocted (clandestine) key made by the U.S. mint to keep interest in the series.
@MasonG said:
Jefferson nickels? You could ask people who collect from circulation about that.
1939-D is kind of tough in au or unc condition aside from full steps or not. Tough enough to call the key of the regular issue Jefferson nickels, in my opinion. I found a 1939-D (VF or so) in circulation when I was a kid. My buddy who had his own Jefferson nickel set going from circulation and didn't have a '39-D for his set, could hardly contain his jealousy when I showed my '39-D to him. A nice unc '39-D is at least a $50 coin these days.1939-D is the key and 1950-D is a semi-key of the regular issue Jefferson nickels is the way I see it.
"Compassionate people are geniuses in the art of living, more necessary to the dignity, security, and joy of humanity than the discoverers of knowledge."
@Colonialcoin said:
Lincoln cents. A date set of these could easily be put together at a very large show unless one is looking for superb examples.
One should be able to put together a date set of Lincoln cents at even a small show.
"Compassionate people are geniuses in the art of living, more necessary to the dignity, security, and joy of humanity than the discoverers of knowledge."
It really all depends how you define key date. If it is describing the lowest mintage date, as I used to define it, all sets with more than one year will have a “key date”.
I mostly believe it is a marketing term.
Many of the coins we consider key dates aren’t rare at all and can be found in bulk on any given day online or at a large show.
What a lot of people are describing as keys in modern coins I would consider condition rarity. Not keys.
@Crypto said:
Peace dollars don’t really have a key, just a few that are more popular.
I respectfully have to disagree.
Keydatecoins.com says 1928 is the KEY date for Peace Dollars. I have to agree.
I have never seen one for sale. I have 27 and a couple of 21's, but no 28's. https://keydatecoins.com/1928-peace-dollar/
Again as @bigjpst said, it all depends on the definition of "key date". Its in the eyes of the beholders, but I think there is always one date that has not only the lowest mintage, but the fewest in higher grades. Its not about variety, design, etc. though the 1909-S Lincoln certainly is key date material. Especially the VDB, even in lower grades,
“When you don't know what you're talking about, it's hard to know when you're finished.” - Tommy Smothers
@bigjpst said:
It really all depends how you define key date. If it is describing the lowest mintage date, as I used to define it, all sets with more than one year will have a “key date”.
I mostly believe it is a marketing term.
Many of the coins we consider key dates aren’t rare at all and can be found in bulk on any given day online or at a large show.
What a lot of people are describing as keys in modern coins I would consider condition rarity. Not keys.
I think we need to rethink the definition of key date for modern coins. The mintages are sometimes in the billions. And there are lower mintage years/mints that no-one even cares about. (though they are being collected, and fetch a slight premium for relative scarcity). Eg. lower mintage West Point coins such as the quarters.
Incomplete list of coins that have less than 2 million in existence that were not proofs:
2019 W Quarters — America the Beautiful Series
Design Mintage Notes
Lowell National Historical Park 2,000,000 First W quarter ever released.
American Memorial Park 2,000,000 Low‑population in high grade.
War in the Pacific 2,000,000 Popular design.
San Antonio Missions 2,000,000 Strong collector demand.
Frank Church River of No Return Wilderness 2,000,000 Final 2019 W issue.
Eisenhower $1 1973‑P P 1,769,258 Mint‑set only; key.
Eisenhower $1 1973‑P1973‑D D 2,002,000 Mint‑set only; key.
You cant just call them key dates, but they are key mint-dates. Add the adjective "modern" (ambigous as it gets) and you have "modern key mint-dates".
“When you don't know what you're talking about, it's hard to know when you're finished.” - Tommy Smothers
@Crypto said:
Peace dollars don’t really have a key, just a few that are more popular.
I respectfully have to disagree.
Keydatecoins.com says 1928 is the KEY date for Peace Dollars. I have to agree.
I have never seen one for sale. I have 27 and a couple of 21's, but no 28's. https://keydatecoins.com/1928-peace-dollar/
Again as @bigjpst said, it all depends on the definition of "key date". Its in the eyes of the beholders, but I think there is always one date that has not only the lowest mintage, but the fewest in higher grades. Its not about variety, design, etc. though the 1909-S Lincoln certainly is key date material. Especially the VDB, even in lower grades,
I consider 1909-S pennies to be keys. V.D.B. not necessary to call 1909-S Lincoln penny a key.
"Compassionate people are geniuses in the art of living, more necessary to the dignity, security, and joy of humanity than the discoverers of knowledge."
I see 1893-S Morgans at coin shows more than I see 1896-S Morgans, so the definition of “key date” has always been a relative term to me. Same with 09-S VDB Lincoln cents vs. 1931-S cents. I hardly ever see the latter for sale…
True “keyless” sets would be anything modern & mass produced, mostly post-1964.
Always looking for attractive rim toned Morgan and Peace dollars in PCGS or (older) ANA/ANACS holders!
"Bongo hurtles along the rain soaked highway of life on underinflated bald retread tires."
@Crypto said:
Peace dollars don’t really have a key, just a few that are more popular.
I respectfully have to disagree.
Keydatecoins.com says 1928 is the KEY date for Peace Dollars. I have to agree.
I have never seen one for sale. I have 27 and a couple of 21's, but no 28's. https://keydatecoins.com/1928-peace-dollar/
Again as @bigjpst said, it all depends on the definition of "key date". Its in the eyes of the beholders, but I think there is always one date that has not only the lowest mintage, but the fewest in higher grades. Its not about variety, design, etc. though the 1909-S Lincoln certainly is key date material. Especially the VDB, even in lower grades,
This definition does not fit Seated Liberty halves. The key date that is considered collectible, the 1878-S, does not have the lowest mintage. There are nine other dates with lower mintages, and two other dates with the same mintage as the 1878-S. Furthermore, mint state coins comprise the largest group by grade (13 examples) within the 55 examples known.
I consider 1909-S pennies to be keys. V.D.B. not necessary to call 1909-S Lincoln penny a key.
From wheat cents, I consider the 1909-S, 1909-S VDB, 1914-D, 1922 "No D", 1931-S, and 1955 DDO "key", by reputation only. Numerous semi-keys for the same reason, from an inference that these coins were not available or difficult to find in circulation which I presume was reflected in 60's and earlier Red Books.
@MasonG said:
Jefferson nickels? You could ask people who collect from circulation about that.
1939-D is kind of tough in au or unc condition aside from full steps or not.
I suspect most people collecting from circulation are not expecting they'll be able to assemble an au/unc set.
I briefly looked through Jefferson nickel rolls in the late 70's as a YN. I did find 1939's then, but nowhere near AU or MS.
I started collecting Jeffersons in the 60s. Finding AU/UNC 39's at that time was pretty much unheard of.
That's what I would expect for any US circulating coin of that age (20+ years), then or now. With such a large collector base, someone is going to grab it.
The Shield Cents don’t have a key? Could we count the 2019 W Uncirculated Cent? Maybe we don’t include this somehow, but the actual number removed from the original packaging has reduced the already small amount of those available. Someday it certain will be more “included” in the Lincoln business strike collection. $40 bucks on eBay……Think about it, 4000X its face value! BTW on eBay currently……there are TEN ( yes, only 10), 2019W Uncirculated cents (certified or in original packaging) for sale. Ten ••••••••••Update, just bought one for myself. PCGS MS68 RD
@Crypto said:
Peace dollars don’t really have a key, just a few that are more popular.
I respectfully have to disagree.
Keydatecoins.com says 1928 is the KEY date for Peace Dollars. I have to agree.
I have never seen one for sale. I have 27 and a couple of 21's, but no 28's. https://keydatecoins.com/1928-peace-dollar/
Again as @bigjpst said, it all depends on the definition of "key date". Its in the eyes of the beholders, but I think there is always one date that has not only the lowest mintage, but the fewest in higher grades. Its not about variety, design, etc. though the 1909-S Lincoln certainly is key date material. Especially the VDB, even in lower grades,
There are over 500 for sale on eBay right now, according to the search results.
I think Jefferson Nickels are the obvious choice. I thought the 50-D was a "key date" as a kid (collecting from circulation on the East coast), but then I went to my first coin show and saw rolls of them... lol!
Collecting: Dansco 7070; Middle Date Large Cents (VF-AU); Box of 20;
Comments
Lincoln Memorial Cents?
Roosevelt Dimes?
State Quarters?
It depends somewhat on how you define Key.
I am assuming a Key is significantly rarer than the median.
And that the series is just dates and mint marks, not die varieties which can be somewhat rare like the 1c 1972 DDO.
Roosies?
Jim
When a man who is honestly mistaken hears the truth, he will either quit being mistaken or cease to be honest....Abraham Lincoln
Patriotism is supporting your country all the time, and your government when it deserves it.....Mark Twain
IKE dollars. Putting a set together is very easy.
"When they can't find anything wrong with you, they create it!"
I'm confused by the question. Are you asking which coin series do not have key dates?
American Innovation Dollars.
All low mintage and NIFC.
Coins are Neato!

"If it's a penny for your thoughts and you put in your two cents worth, then someone...somewhere...is making a penny." - Steven Wright
Jefferson
Need more definition, including condition.
Jefferson Nickels.
"Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety," --- Benjamin Franklin
Jefferson nickels? You could ask people who collect from circulation about that.
Franklin Half Dollars. A nice BU set can be put together for relatively cheap. I own four sets. No reason to own four, I just have them.
Kennedy Halves, Franklin Halves, Roosevelt Dimes, Jefferson Nickels, Ike/SBA/Sac/Pres. Dollars.
Collector, occasional seller
"Key" is a relative term. Most modern series could cite the 1981-S Type 2 as a key for example
Custom album maker and numismatic photographer.
Need a personalized album made? Design it on the website below and I'll build it for you.
https://www.donahuenumismatics.com/.
Unless you don't collect varieties.
Flying Eagle cents (if you assume the '56 is a pattern)
Dave
Non FBL Franklins.
Sometimes, it’s better to be LUCKY than good. 🍀 🍺👍
My Full Walker Registry Set (1916-1947):
https://www.ngccoin.com/registry/competitive-sets/16292/
The concept of "key" is better viewed as marketing. Any series can be considered to include "keys" if the definition is narrow enough. Now, it just seems to be which ones are the most expensive, as outside of legitimately (somewhat) difficult to buy coins, all others can be bought in a quality collectors traditionally accepted at any time or short notice.
Another way of looking at it is how many US series can be completed in high quality (subjectively in an MS holder from any leading TPG) in one day. I've looked intermittently on eBay and Collector's Corner and the list sure isn't short. It includes series most US collectors consider scarce.
I consider the most relevant usage of "key" to be the one I infer was used for 60's US circulating designs. This includes wheat cents, Buffalo nickels, Mercury dimes, SLQ, and WLH. To this I'd add the Morgan and Peace dollar, IHC, Barber series, and the Indian Head quarter eagle.
Why? Because they are looking for FS coins or dates no one should expect to find in circulation anymore?
Door #2.
Schlage.
Just remember...the advice you receive on the site is worth every bit of what you paid for it.
I have watched the 1949-PDS Franklins move from #1 to #3 over the years. I paid way too much for a 1949-S when it was hot. The 1949-D was last then. It became #1 later. It changes too much for me to care.
2021 Washington Crossing the Delaware Quarter
(both a series, and a non-key date)
A date and mint mark set of Barber half dollars basically has no keys. However a nice collectible 74 coin set in G4 would run about $5500 according to the PCGS price guide.
I was going to buy a 1949-S FBL in 65 or 66 but, when I saw a 66 (without FBL designation), in a PCGS/CAC holder, I jumped at it. It has nice original toning. The 1949-S was always considered the key (for non-FBL coins), as long as I can remember. I'll buy FBLs, when possible, but they aren't an important criteria for me, as I simply don't care that much. The 1953-S is the perfect example. A 65 FBL is $32K and even a 64 FBL is $20K. That's nuts. With enough searching you can find a plain one that is close without the HUGE premium.
Sometimes, it’s better to be LUCKY than good. 🍀 🍺👍
My Full Walker Registry Set (1916-1947):
https://www.ngccoin.com/registry/competitive-sets/16292/
What about the gold Presidental Spouse series? No real keys, even if you look at the low mintages of the last few years, but expensive as bullion has placed them around $2500. melt.
Most were not keys ‘til the collecting public could not find them in circulation anymore. Or, until
they were discovered as a variety or error that was generally accepted into sets. (3-legged Buffalo, overdates, doubled dies or low mintage numbers; as examples ). There just aren’t enough 1914-D Lincoln cents for every cent collector. But it’s the 1909-S VDB we call “the key”. Some think the high and low leaf Wisconsin 2004-D SHQ was a concocted (clandestine) key made by the U.S. mint to keep interest in the series.
``https://ebay.us/m/KxolR5
Chain cents unless they’re all keys 😝
Empty Nest Collection
1939-D is kind of tough in au or unc condition aside from full steps or not. Tough enough to call the key of the regular issue Jefferson nickels, in my opinion. I found a 1939-D (VF or so) in circulation when I was a kid. My buddy who had his own Jefferson nickel set going from circulation and didn't have a '39-D for his set, could hardly contain his jealousy when I showed my '39-D to him. A nice unc '39-D is at least a $50 coin these days.1939-D is the key and 1950-D is a semi-key of the regular issue Jefferson nickels is the way I see it.
"Compassionate people are geniuses in the art of living, more necessary to the dignity, security, and joy of humanity than the discoverers of knowledge."
Albert Einstein (14 March 1879--18 April 1955)
Lincoln cents. A date set of these could easily be put together at a very large show unless one is looking for superb examples.
One should be able to put together a date set of Lincoln cents at even a small show.
"Compassionate people are geniuses in the art of living, more necessary to the dignity, security, and joy of humanity than the discoverers of knowledge."
Albert Einstein (14 March 1879--18 April 1955)
I suspect most people collecting from circulation are not expecting they'll be able to assemble an au/unc set.
Peace dollars don’t really have a key, just a few that are more popular.
11.5$ Southern Dollars, The little “Big Easy” set
@renomedphys If Chain Cents do not have a 'key' because they are all keys then I submit Gobrecht Dollars and Stella $4 Gold in this "keyless" club.
www.brunkauctions.com
It really all depends how you define key date. If it is describing the lowest mintage date, as I used to define it, all sets with more than one year will have a “key date”.
I mostly believe it is a marketing term.
Many of the coins we consider key dates aren’t rare at all and can be found in bulk on any given day online or at a large show.
What a lot of people are describing as keys in modern coins I would consider condition rarity. Not keys.
My Ebay Store
I respectfully have to disagree.
Keydatecoins.com says 1928 is the KEY date for Peace Dollars. I have to agree.
I have never seen one for sale. I have 27 and a couple of 21's, but no 28's.
https://keydatecoins.com/1928-peace-dollar/
Again as @bigjpst said, it all depends on the definition of "key date". Its in the eyes of the beholders, but I think there is always one date that has not only the lowest mintage, but the fewest in higher grades. Its not about variety, design, etc. though the 1909-S Lincoln certainly is key date material. Especially the VDB, even in lower grades,
I think we need to rethink the definition of key date for modern coins. The mintages are sometimes in the billions. And there are lower mintage years/mints that no-one even cares about. (though they are being collected, and fetch a slight premium for relative scarcity). Eg. lower mintage West Point coins such as the quarters.
Incomplete list of coins that have less than 2 million in existence that were not proofs:
2019 W Quarters — America the Beautiful Series
Design Mintage Notes
Lowell National Historical Park 2,000,000 First W quarter ever released.
American Memorial Park 2,000,000 Low‑population in high grade.
War in the Pacific 2,000,000 Popular design.
San Antonio Missions 2,000,000 Strong collector demand.
Frank Church River of No Return Wilderness 2,000,000 Final 2019 W issue.
Eisenhower $1 1973‑P P 1,769,258 Mint‑set only; key.
Eisenhower $1 1973‑P1973‑D D 2,002,000 Mint‑set only; key.
You cant just call them key dates, but they are key mint-dates. Add the adjective "modern" (ambigous as it gets) and you have "modern key mint-dates".
I consider 1909-S pennies to be keys. V.D.B. not necessary to call 1909-S Lincoln penny a key.
"Compassionate people are geniuses in the art of living, more necessary to the dignity, security, and joy of humanity than the discoverers of knowledge."
Albert Einstein (14 March 1879--18 April 1955)
I see 1893-S Morgans at coin shows more than I see 1896-S Morgans, so the definition of “key date” has always been a relative term to me. Same with 09-S VDB Lincoln cents vs. 1931-S cents. I hardly ever see the latter for sale…
True “keyless” sets would be anything modern & mass produced, mostly post-1964.
"Bongo hurtles along the rain soaked highway of life on underinflated bald retread tires."
~Wayne
Draped bust small eagle half dollars.
This definition does not fit Seated Liberty halves. The key date that is considered collectible, the 1878-S, does not have the lowest mintage. There are nine other dates with lower mintages, and two other dates with the same mintage as the 1878-S. Furthermore, mint state coins comprise the largest group by grade (13 examples) within the 55 examples known.
I briefly looked through Jefferson nickel rolls in the late 70's as a YN. I did find 1939's then, but nowhere near AU or MS.
From wheat cents, I consider the 1909-S, 1909-S VDB, 1914-D, 1922 "No D", 1931-S, and 1955 DDO "key", by reputation only. Numerous semi-keys for the same reason, from an inference that these coins were not available or difficult to find in circulation which I presume was reflected in 60's and earlier Red Books.
I started collecting Jeffersons in the 60s. Finding AU/UNC 39's at that time was pretty much unheard of.
That's what I would expect for any US circulating coin of that age (20+ years), then or now. With such a large collector base, someone is going to grab it.
The Shield Cents don’t have a key? Could we count the 2019 W Uncirculated Cent? Maybe we don’t include this somehow, but the actual number removed from the original packaging has reduced the already small amount of those available. Someday it certain will be more “included” in the Lincoln business strike collection. $40 bucks on eBay……Think about it, 4000X its face value! BTW on eBay currently……there are TEN ( yes, only 10), 2019W Uncirculated cents (certified or in original packaging) for sale. Ten ••••••••••Update, just bought one for myself. PCGS MS68 RD

I found a full set of Jefferson's in change. Still remember turning over the 1950 and seeing the D.
There are over 500 for sale on eBay right now, according to the search results.
I think Jefferson Nickels are the obvious choice. I thought the 50-D was a "key date" as a kid (collecting from circulation on the East coast), but then I went to my first coin show and saw rolls of them... lol!
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