The U.S. is home to, at last count, 735 billionaires, the most of any country, who have a combined net worth of $4.5 trillion, according to Forbes magazine. By combining business savvy, the outlook of a visionary, good luck, and a sometimes merciless approach to competition, a select few Americans have been able to amass fortunes worth billions.

To determine the 25 richest Americans of all time, 24/7 Wall St. reviewed wealth estimates of prominent Americans, both living and dead, from historical and media sources, including the Forbes Real-Time Billionaires list. We converted the estimated net worth of those who have passed away into current U.S. dollars using the CPI inflation calculator from the U.S. Bureau of Labor Statistics. The figures for those not living are our best attempt to estimate each person’s peak net worth.

The 25 billionaires on the list have amassed fortunes the equivalent of $66 billion, in 2023 dollars, or much more. Of the 25 wealthiest Americans ever, 10 are still alive and hold a combined net worth of more than $1.17 trillion. Many of these billionaires have made their fortunes in the tech sector, which has become a driving force of the American economy. (See where America’s 25 richest billionaires went to college.)

Many of the other richest Americans on our list gained their wealth beginning in the Industrial Revolution and during the Gilded Age of the late 19th century, when bankers and industrialists controlled power and wealth with little interference from government. This was when America’s westward expansion accelerated, and cities swelled with immigrants and those looking for employment opportunities. The richest Americans took advantage of these trends and made their fortunes in coal, steel, oil, railroads, and shipping. 

Some of these so-called “robber barons” amassed their wealth through ethically questionable means, bribing politicians, preventing workers from organizing, and ruthlessly crushing rivals.

Much like the Gilded Age, income inequality has become a major issue in the U.S. today as technology has contributed to creating a more bifurcated income structure. (See the CEOs of major U.S. companies who are paid 1,000 times more than their employees.)

Click here to see 25 richest Americans of all time.