US marathon finisher numbers increased 18 percent in 2025 to reach their highest level since 2015, with growth concentrated among runners aged 25 to 40 who are being introduced to distance running through social media communities, training app ecosystems, and the social infrastructure of running clubs that have proliferated in major cities. Virtual training programs have made structured marathon preparation accessible to runners without access to coaching resources.
The running boom is having measurable effects on related industries including footwear, fitness tracking technology, and nutrition supplements specifically formulated for endurance athletes. Major marathon events including Boston, New York, Chicago, and London face demand pressure that far exceeds their participant capacity, with lottery acceptance rates at most major events below 30 percent. New destination marathons are being launched to meet demand that established events cannot accommodate.
