The following is a list of all light rail systems in the United States, ranked by ridership. Also included are those urban streetcar/trolley systems that are providing regular public transit service (i.e. operating year-round and at least five days/week). This list does not include statistics for metro/rapid transit systems (see: the List of United States rapid transit systems by ridership for those). Daily and annual ridership figures are based on "average weekday unlinked passenger trips" (where transfers between lines are counted as two separate passenger "boardings" or "trips"). The annual ridership figures for 2019 and average weekday ridership figures for the fourth quarter (Q4) of 2019 come from the American Public Transportation Association's (APTA) Ridership Reports statistics for