The Shanghai Metro is the world's longest metro network at 803 kilometres (499 mi) and has the highest annual ridership at 2.83 billion trips. The New York City Subway has the greatest number of stations with 472. As of 2023, the country with the most metro systems is China, with 45 in operation.

The title of the "largest" subway system depends on whether you measure by track length or the number of stations. As of 2026, the Beijing Subway holds the record for the world's longest metro network, spanning over 890 kilometers (approx. 550 miles). It is a massive, modern feat of engineering that carries billions of passengers annually. However, if you measure by the total number of stations, the New York City Subway remains the largest, boasting 472 stations (or 424 if counting transfer complexes as single stations). While the NYC system is older and covers a vast geographic area, the sheer scale of expansion in Chinese cities like Beijing and Shanghai has redefined global transit metrics. Shanghai follows closely as the second-longest system. In terms of "busiest," the Tokyo Subway often takes the lead for ridership density, but for raw infrastructure size in 2026, Beijing is the undisputed champion of the modern rail era.