The following is a list of all heavy rail rapid transit systems in the United States. It does not include statistics for bus or light rail systems; see: List of United States light rail systems by ridership for light rail systems. All ridership figures represent unlinked passenger trips, so line transfers on multi-line systems register as separate trips. The data is provided by the American Public Transportation Association's Ridership Reports.
Note: ridership does not mean unique passengers, it means total number of trips.