The Largest Races data portal currently contains information on finisher totals from U.S. race events held in 2015 and 2016. Due to a change in the Running USA methodology for collecting data in 2017 to reflect registration numbers rather than finisher totals, 2017 races are not currently part of this portal.
To use this portal, select the start and end dates for the calendar year you wish to search, as well as any other mandatory category fields. For distances, enter at least part of the distance you wish to search. For example, for half marathon, enter "half", for 10K enter "10", for marathon enter "mara."