
1. John D. Rockefeller —
Rockefeller made his fortune by revolutionizing the oil industry. Before his time, lamp oil was unpredictable. But he figured out a way to standardize the quality, and Standard Oil was born.

2. Cornelius Vanderbilt —
Vanderbilt got his start sailing barges across New York Harbor, and gradually expanded into steamships and railroads. One of his favorite business tactics was to undercut the competition so heavily that they would pay him to stay out of a given market.

3. John Jacob Astor —
Astor got his start as a fur trader after hearing a fellow traveler talk about the profession on his voyage to America. A penniless German immigrant, his business endeavors were helped when he married his wife, who came from a wealthy family.

4. Stephen Girard —
The French-born Girard started as a cabin boy working the Europe-Caribbean trade route, and became a sea captain by the age of 23. Eventually he owned a fleet of trading ships.

5. Richard Mellon —
Richard and brother Andrew (No. 15) were Pittsburgh bankers that had a hand in a variety of burgeoning 19th century industries, including steel, oil, coal and railroads.

6. Andrew Carnegie —
Founder of the Carnegie Steel Company, Carnegie is perhaps even more famous for giving his fortune away.

6. Stephen Van Rensselaer —
Van Rensselaer was the last in a line of aristocrats that had been given vast land grants in the New World under Dutch colonial rule. At one point he controlled over a million acres in New York State and had up to 100,000 tenants living on his land. He's the only member on this list to entirely inherit his fortune.

8. Alexander Turney Stewart —
An Irish-born textile merchant, Stewart went on to run one of the biggest wholesale and retail dry goods businesses in the United States and was a major uniform supplier to the Union Army during the civil war.

9. Frederick Weyerhäuser —
Timber, lumber and paper magnate Frederick Weyerhäuser and his family were once rumored to control an area the size of Wisconsin.

10. Jay Gould —
Gould was a railroad executive, financier and speculator, and considered one of the most unscrupulous businessmen in U.S. history.

11. Marshall Field —
Field founded the now-closed Marshall Field's department store chain, with a flagship store in Chicago.

12. William Henry Gates III —
The Microsoft co-founder is currently the world's richest man, according to several different rankings.

13. Henry Ford —
Ford's name is synonymous with his famous Model-T car and the automaking behemoth he founded, but his greatest contributions to the country were arguably two other ideas.

14. Warren Buffett —
Buffett has turned his 1965 purchase of clothing company Berkshire Hathaway into one of the most successful investing vehicles of all time. From the 1960s through the 1990s, major stock indexes averaged an 11% annual gain, while Berkshire's stock averaged 28%.

15. Andrew Mellon —
Though he lived just five years longer than his brother Richard (No. 5), Andrew's ranking is 10 spots lower because the U.S. economy recovered greatly during this time period, lowering his relative wealth.

16. Samuel M. Walton —
Fresh out of college, the Wal-Mart founder cut his teeth in a J.C. Penney management training program. Later, he ran a chain of five-and-dime stores in the South.

17. Moses Taylor —
The son of an aide to John Jacob Astor (No. 3), Taylor used his own and his family's money to invest in a wide range of industries: sugar, coffee, shipping, railroads, steel, coal and utilities, to name a few.

18. Russell Sage —
Born poor in upstate New York, Sage started out as a grocery store clerk. But he was a prodigious worker, saver and trader, and soon had enough money for his own shop. From there, he expanded into horse brokering, shipping and making loans to friends.

19. James G. Fair —
Fair, along with three other partners, made his money on a Nevada silver and gold mine -- at that time the largest mining discovery in U.S. history.

20. William Weightman —
Weightman founded a drug company that developed a synthetic form of quinine, which is used to treat malaria. The firm was later absorbed into Merck.


