How 28 Americans amassed the greatest fortunes in US history, from railroads to tech
Business Insider• Jan 15, 2026• 6 min read
Standard Oil founder John D. Rockefeller has long been considered the wealthiest man in America's history, but Elon Musk is now wealthier.
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America has more billionaires than ever, led by Elon Musk, who's estimated to be worth $716 billion.
Figures such as John D. Rockefeller and Andrew Carnegie were known as the richest men of their time.
Today's tech leaders are among the richest Americans in history — see the full list.
America has never had as many billionaires as it does now.
But how does the wealth of historic figures, such as the industrialists of the Gilded Age, compare to that of the richest people in 2025? That is to say: Who are the richest Americans of all time?
In many historic calculations of net worth, individual fortunes weren't measured in isolation; instead, they were compared to the GDP of the US at the time. When the US economy was much smaller than it is today, the wealthiest families and individuals carried more weight in the economy than others during more prosperous times.
One of the richest Americans of all time is widely considered to be Standard Oil founder John D. Rockefeller, whose wealth, at its peak in 1937, was equal to 1.5% of the country's GDP. His estimated net worth would be around $499 billion today, when adjusted for inflation.
Elon Musk's current wealth, however, is understood to have now eclipsed that of Rockefeller's. On January 14, Forbes estimated Musk's fortune to be $716.7 billion.
To identify some of the richest Americans of all time, we consulted Forbes' 2007 list of history's wealthiest figures, based on estimates by economist Peter Bernstein. It calculated individuals' wealth at their peak and compared it to the country's GDP at the time to convert it to 2006 dollars. This was then adjusted to today's dollars using the US Bureau of Labor Statistics' inflation calculator.
For living individuals, we cited estimated net worths reported by Forbes as of January 14.
While estimations of historic wealth may not be perfect, they help paint a picture of the level of wealth enjoyed by some of America's most notable figures in business, and put it into context with today's billionaires.
Here are 28 of the wealthiest Americans in history.
Andrew W. Mellon (1855-1937)
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Estimated net worth (2025 adjusted estimate): $82.5 billion
Source of wealth: Banker and industrialist; heir to the Mellon banking dynasty
Henry Ford (1863-1947)
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Net worth (adjusted estimate): $88.8 billion
Source of wealth: Automaker; founder of Ford Motor Company
Jay Gould (1836-1892)
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Net worth (adjusted estimate): $95.1 billion
Source of wealth: Railroad financier and speculator
