Shelton, 27, of Morristown, New Jersey, said she did not realize victory was within reach until about a half-mile from the finish. Thistel, 25, of Lancaster, Pennsylvania, had led for much of the race.

“I could see first place right in front of me,” Shelton said afterward. She described the closing miles as a blur, adding that she focused on keeping her pace while wondering whether Thistel might have enough energy to sprint past her.

The men’s race also featured a close contest. Devin Horseman-Guy, 27, of Baltimore, pulled away from Patrick Blair, 45, of Catonsville, after the halfway point to take the win.

Horseman-Guy said training on Baltimore’s hills and familiarizing himself with the course helped him manage the challenging climbs. Friends and spectators cheered him toward the finish in his hometown.

“I live here in the city, so I trained here all year,” he said. “It was kind of my backyard.”

More than 14,900 runners from across the country and around the world gathered in Baltimore for the Running Festival, which included races beyond the marathon. Spectators and local running groups lined the course, including near Mile 24, where volunteers and fellow runners offered encouragement to athletes approaching the finish.