How Many People Have Ever Lived in the United States?

On July 4, 2026, the United States turns 250. This anniversary made me think about how many people it took to build this country, and how many of them are no longer here to see what it has become.In other words: how many people have ever lived in the United States?For most of the country's history, demographic record-keeping was unfortunately far from complete, especially when it came to births. But the census has counted the population since 1790, and combining those counts with historical birth-rate estimates and immigration records gives a reasonable figure: about 644 million people have lived in the United States since it became independent in 1776. A little over half of them, about 53 percent, are alive today. And of the 548 million children born in the United States, roughly one in eleven, some 49 million, died before reaching the age of five. Had those same children been born under today's conditions, only about three million would have died so young.What goes into the estimateAny estimate of the total number of people who have ever lived in a country depends on only a few factors: the length of time the country has existed, the size of its population at different points, and the number of births per 1,000 people during each of those periods. It also depends on immigration, since someone can become part of a country's population either by being born in it or by moving to it.So the whole calculation comes down to three pieces: the roughly 2.5 million people already alive in the country at its founding in 1776, everyone born on United States soil since then, and everyone who immigrated to live there. The first is small and fixed; the other two are running totals that have to be built up over time. My starting point was an earlier estimate by jlredford, writing in 2010 on the blog A Niche in the Library of Babel, which placed the born-in-country total at about 472 million and immigrants at about 73 million, for roughly 545 million people up to 2010. That estimat