Richest Americans of all time

While Bill Gates and Warren Buffett are known as one of the richest Americans, but who are the wealthiest of all time?

Let's take a look at some of the richest Americans in history.

Source: Business Insider

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John D Rockefeller

Fortune: $336 billion

Born: 1835

Source of wealth: He founded Standard Oil in 1870, at the age of 31, and bought up most of the oil refineries in the United States, eventually controlling about 90 per cent of the American oil business.

Global rank: 1

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Andrew Carnegie

Fortune: $309 billion

Born: 1835

Source of wealth: Carnegie invested in the steel business when the market was booming, eventually ending up at the head of the US Steel empire.

Global rank: 2

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Cornelius Vanderbilt

Fortune: $185 billion

Born: 1794

Source of wealth: In 1862, he began to buy railroad lines. Although already 70 years old, his wealth mostly comes from this business of the 19th century. Prior to that, he was known as a cold-blooded steam-boat entrepreneur.

Global rank: 3

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Bill Gates

Peak fortune: $136 billion

Born: 1955

Source of wealth: Founded Microsoft with Paul Allen in 1975. He held onto shares as Microsoft dominated the age of computers, peaking in personal wealth at the top of the Dot Com Bubble.

Global rank: 4

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John Jacob Astor

Fortune: $121 billion

Born: 1763

Source of wealth: A successful fur trader, he established a near monopoly within the US by around 1800. He subsequently switched trades and went on to investing in real estate, focusing on New York City.

Global rank: 5

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Stephen Girard

Fortune: $105 billion

Born: 1750

Source of wealth: Successful in the shipping trade, he was a French-born American merchant who went into the banking business later in his life, owning a bank that was called 'Girard's Bank'.

Global rank: 6

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AT Stewart

Fortune: $88.9 billion

Born: 1803

Source of wealth: An American entrepreneur, he founded the first department store in lower Manhattan and subsequently expanded his retail business.

Global rank: 7

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Frederick Weyerhaeuser

Fortune: $79.4 billion

Born: 1834

Source of wealth: He founded Weyerhaeuser Company, one of the biggest timber companies in the United States, after he arrived to America from Germany in the 19th century.

Global rank: 8

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Jay Gould

Fortune: $71.2 billion

Born: 1836

Source of wealth: Railroad baron and gold speculator, Jay Gould masterminded the 19th century transportation boom in America. He and financier James Fisk also bought up a dominating share of the gold market at the time - enough to directly affect market movements during Gould's lifetime.

Global rank: 9

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Stephen Van Rensselaer

Fortune: $68.5 billion

Born: 1764

Source of wealth: Major of the US Militia and member of the New York State Assembly, Rensselaer was also heir to one of the most well-endowed estates in the US. He founded the Rensselaer Polytechnic Institute with a portion of his wealth.

Global rank: 10

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Marshall Field

Fortune: $66.1 billion

Born: 1834

Source of wealth: He started the retail store chain Marshall Field and Company in Chicago during the Civil War.

Global rank: 11

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Sam Walton

Fortune: $64.5 billion

Born: 1918

Source of wealth: Founded Walmart in 1962 and lived a famously humble life. As Walmart keeps growing, Walton's four children have individual fortunes around $20 billion each.

Global rank: 12

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Warren Buffett

Fortune: $63.9 billion

Born: 1930

Source of wealth: Investments. The Oracle of Omaha joined Berkshire Hathaway as chairman in 1970 and hasn't looked back. He has pledged to give away 99 per cent of his money.

Global rank: 13