The Conlon Collection is considered one of the most valuable private collections of baseball cards in existence. Amassed by Bill Conlon over several decades, the collection contains over 350,000 cards and is valued at over $20 million. Let’s take a deeper look at some of the key cards in the collection and what makes them so valuable.

One of the most prized possessions in the Conlon Collection is a 1909-11 T206 Honus Wagner card that is considered the rarest and most valuable baseball card of all time. In near mint condition, it is estimated to be worth over $3 million on its own. What makes this particular Wagner card so special is its state of preservation. Most Wagner cards that still exist today are in very poor condition after over 100 years. The Conlon’s Wagner rates an SGC grade of EX-MT 5.5, meaning it is remarkably well-preserved for its age. Its centering, edges and face are clean and sharp.

Another iconic card in the collection is a 1952 Topps Mickey Mantle in near mint condition. The ‘52 Mantle is one of the most desirable post-war cards as it captures the young Yankees star at the beginning of his Hall of Fame career. An SGC-graded example like the Conlon’s would be valued at around $150,000-$200,000 today. Its high grade and the iconic subject make it a true blue chip item.

A third truly elite card is a 1933 Goudey Babe Ruth. High grade Goudey Ruths from the 1930s are exceedingly rare finds in the collecting world. The Conlon card checks in at a stellar SGC grade of EX-MT 6. With beautiful centering, sharp corners and vivid color, it exemplifies what collectors dream of finding in vintage cardboard from nearly 90 years ago. As one of the finest known examples, its estimated worth would be $300,000-$500,000.

While those three cards alone would make any collection extraordinarily valuable, the true breadth of the Conlon Collection lies in its incredible depth. It contains examples of virtually every notable pre-war and early post-war set in high grades across the entire spectrum of Hall of Famers and franchise stars. Here are just a few examples:

1914 Cracker Jack Eddie Plank (SGC EX 5): $25,000+
1915 Cracker Jack Walter Johnson (PSA VG-EX 3.5): $15,000+
1916 M101-4 Babe Ruth (PSA EX 4): $50,000+
1917 W515 E90 Eddie Collins (PSA EX 5): $20,000+
1924 W516 Cracker Jack Walter Johnson (PSA EX 4): $30,000+
1933 Goudey Dazzy Vance (PSA EX 5): $8,000+
1941 Play Ball Hank Greenberg (PSA EX 5): $7,000+
1952 Topps Willie Mays (PSA EX 5): $15,000+
1956 Topps Sandy Koufax (PSA EX-MT 6): $10,000+
1964 Topps Roberto Clemente (PSA EX 5): $5,000+

You get the idea. Row after row of immaculately preserved cardboard greats from over a century of the game. And that doesn’t even touch on the uncounted thousands of star and commons cards that further illustrate the history of the sport. No other collection, public or private, can claim such depth and breadth of high grade vintage cards from before the modern era of the 1970s.

While the individual value of cards like the Wagner, Mantle and Ruth help define the Conlon Collection as an eight-figure asset, it’s the incredible completeness and quality of the entire assemblage that makes it so uniquely valuable. In today’s stratospheric vintage card market, finding a single collection with so many significant rarities in top-notch condition is virtually unheard of. That’s what sets the Conlon Collection apart as not just the most complete, but quite likely the most valuable collection of baseball cards ever amassed by one person. Its estimated worth of over $20 million is a testament to a lifetime of careful collecting and preservation by its founder, Bill Conlon.