Along the Washington and Old Dominion Trail, he walks in a rhythmic, deliberate step. The kind of cadence learned in the military.
A young, bearded man, wearing fatigue pants, carrying a large American flag, on a mission.
"This is the very least I can do", says former Marine Justin Kuhel. "I owe them."
Kuhel, 23, served two combat tours in Afghanistan and Iraq.
He was never wounded.
His walk is a way of paying tribute to friends who were killed or wounded in battle.
"It could've been me just as easily that was injured", Kuhel says. "And I'd want somebody doing that for me".
Since March 6, he's walked, from his home in Columbus, Ohio, 25 miles a day.
Herndon resident Dave Nolan is among those who were watching Kuhel's quiet progress.
"I guess there's no Washington and Old Dominion Trail the majority of the way, doing it along highways and things" he says.
Kuhel is hoping to reach Arlington National Cemetery by Monday, the end of a 400-mile journey.
But he has another goal.
"I'm really trying to raise awareness", he says.
He's using this walk to raise $10,000 to benefit the Wounded Warriors Project, a non-profit that supports veterans after they return home.
"Just let these guys know we're still thinking--- people are still thinking of them", Kuhel says.
Alex Matini, who bicycles 50 miles a clip on the trail, sees Kuhel as a hero in more ways than one.
"He's braver than I am", Matini remarked. "And probably much better shape than we are."
Kuhel and fellow former Marine Steve Stuckey are taking this journey together.
They say generous people--- hearing their story--- have given them food and shelter along the way.
Stuckey, behind the wheel, keeps an eye on Kuhel, to make sure he's safe.
"I think we're both just motivated to help out any way we can", he says.
On Monday, the two men plan to finish their journey, visiting graves of fallen comrades at Arlington National Cemetery, a solemn visit.
"It's going to be nice to finally see our brothers who are there, buried there", he says. "I'm going to be thinking about the time we spent in Afghanistan."
Kuhel's journey is being followed on the Internet via both Twitter, and Facebook.
He's already raised $9,000, and has high hopes of surpassing his $10,000 goal.
He says that Monday--the culmination of his long walk, a time of remembrance for the fallen--will be an emotional day.
"It helps me to think about them everyday", Kuhel adds. "Like they deserve to be thought about."
To learn more about the journey and how to donate, visit Kuhel's Facebook page.