Allison Mercer is 43 years old and running faster — and longer — than ever.
The Marietta-based ultra-runner will represent Team USA at the 2026 100K World Championships in Ames, Spain, on Sept. 20.
Mercer qualified for her third consecutive national team with a runner-up finish and master’s win at the 2026 USATF 100K championships in Madison, Wisconsin, in April.
“When I made my first team and ran in India, it was an amazing experience,” Mercer said of racing her first World 100K championships in 2024, where her third-place master’s finish helped the U.S. women’s team secure a bronze medal.
“The women on the team were incredible, we became like a family, and I learned from them since most had been on teams before, even though I was one of the oldest but still a rookie,” she said.
Going the distance
Mercer started running in middle school and lettered in cross country at Woodward Academy.
“I’m running five to six minutes faster in the 5K now than in high school, and that was over 20 years ago,” Mercer said.
She started running seriously in 2017, when she had more time to train consistently and discovered that her body thrived at longer distances like marathons and ultra-marathons.
“The biggest game changer for me was doing more trails — they let me go longer without dying, and built strength and endurance,” she said.
Trail running also introduced her to her husband Ben Mercer, who is also an accomplished runner. Together, the pair have completed the Georgia portion of the Appalachian Trail.
“Running opened up a new community for me,” Mercer said. “All these guys are super fast and intimidating, but welcoming,” she said.
Representing team U.S.A.
To train for the 100K championships, Mercer peaked at 100 miles a week with a long run of 29 miles, many of which were on trails at the Chattahoochee River National Recreation Area near her home.
“What I love about the river is that I know every person over 50 there, because I see them almost every morning,” said Mercer.
She also appreciates the peaceful scenery and soft surface — which is easier on the joints — and the community of people who encourage her running goals.
That support extends to her workplace, Amazon, where Mercer works full-time as a project manager.
“My boss is super supportive and excited about my race and is amazed at what I can accomplish, plus it’s nice to have that flexibility with my schedule,” Mercer said.
For Mercer, who volunteered at the Paralympic Games held in Atlanta, competing as a U.S. athlete is a full-circle moment.
“Growing up watching the Olympics I never thought I’d wear the USA kit and represent my country on an international stage,” Mercer said.
