The challenge was intended to mark the 250th anniversary of US independence.
By completing 50 marathons in all 50 states, Sobania became only the second person to accomplish the feat after American ultramarathon runner Dean Karnazes, who did so in 2006 and whom Sobania has cited as an inspiration.
Sobania, however, completed the challenge in 49 days—one day faster than Karnazes, according to his team.
The 27-year-old set off on May 10 from San Francisco's Golden Gate Bridge, planning to run one marathon a day while traveling between states in a camper van with his support team.
The final marathon, originally scheduled to finish in New York's Times Square on June 28, was completed a day early after Sobania decided to accelerate his schedule and surpass Karnazes' record, his team said.
"We've made history! Now it's time for recovery, and you'll hear from us soon," the team wrote on social media.
Sobania has gained international recognition through a series of endurance challenges.
In March last year, he completed a run across the United States, setting off from New York's Central Park on September 15, 2024 and finishing nearly five months later in San Diego.
He said he ran the equivalent of 125 marathons over 139 days, covering more than 5,250 kilometres, becoming the first Pole to complete such a crossing.
Tomasz Sobania (left). Photo: PAP/Marcin Cholewiński
His previous challenges included a 2023 run from Chorzów in southern Poland to Marathon, Greece, and back; a 60-day run in 2022 from the Polish city of Gliwice to Barcelona, Spain; and a run to Rome a year earlier, during which he raised funds for a child with cancer and attended a papal audience.
(gs)
Source: PAP