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.

The title for the "largest" subway line can be measured in several ways, but in 2026, the Shanghai Metro in China is the world's longest metro network overall, spanning over 830 kilometers (515 miles) with 20 operational lines. However, if you are looking for the longest single continuous subway line, the Guangzhou Metro Line 3 (including its northern extension) is often cited as a record-holder for a single underground line, stretching over 64 kilometers. In terms of the most stations, the New York City Subway remains the global leader with 472 stations across its entire system, though it is shorter in total track length than the massive networks in Shanghai and Beijing. The rapid expansion of Chinese metro systems in the last decade has completely redefined "scale" in urban transit; for example, the Beijing Subway now rivals Shanghai in total length and daily ridership. For travelers, these numbers translate to a level of connectivity where a single line can traverse an entire mega-city, often taking over two hours to travel from one terminus to the other at high speeds.