What country has the longest metro system?

Located in China's most populous urban area, the Shanghai Metro system is the world's most extensive metro system by route length, totaling 498 miles. It is also the second biggest by the number of stations, with 396 stations on 19 lines. Over 10 million people use the system on an average workday, and on March 8, 2019, the daily ridership record was set at 13.29 million.

Source: Wikipedia