Japan leads at 84.9 years — and it is the only country to reach that level at a population of over 100 million. South Korea, Switzerland and Australia follow closely, with the entire top seven packed into a single year. The geography is the blunt message here: of the 20 slots, Europe takes 13, Asia 4, Oceania 2, and the Americas just one, Canada. Two things are widely misread. First, the United States does not make the top 20, sitting near 79 years, almost six behind Japan — a clear laggard among high-income countries. Second, who is "number one" depends entirely on the inclusion rules: Hong Kong (about 85.6 years) and Macao would outrank Japan if territories counted, and microstates such as Monaco and San Marino post higher figures still, but on samples far too small to be stable. For scale, world average life expectancy is about 73 years, nearly 12 below the leader, and Japan alone has more than 90,000 registered centenarians, close to nine in ten of them women.