The best current estimate is about 1.2 million Americans in Mexico , though different sources give a wider range depending on whether they count only residents or also temporary and undocumented stays. Some reports put the number closer to 700,000–800,000 based on census-style counts of U.S.-born or U.S. citizen residents, while U.S. government-linked estimates cited in recent reporting go as high as 1.6 million.

Why the numbers differ

Mexico and U.S. sources do not measure the same thing. Some count only people who are officially recorded as residents, while others try to include temporary residents, long-term visitors, and people without formal status.

Practical answer

If you want a single plain-English number, “around 1 million Americans live in Mexico” is a fair shorthand. If you want the most recent broader estimate, roughly 1.2 million is better supported by recent reporting.

Source note

Recent coverage also says Americans are the largest foreign group in Mexico, which is why this question keeps trending in migration discussions.