Runners of half- and full marathons will travel 13.1 and 26.2 miles, cruising past the Betsy Ross House and Liberty Bell, moving through neighborhoods including Fairmount Park, University City, and Manayunk.
The race starts and ends near the Art Museum.
Duchman, of Southwest Center City, will run the half-marathon. And she'll be among plenty of veterans.
Marine Corps veteran David Lauck is running in honor of his father and uncle. Army veteran Deborah McCaghren is racing with 15 other Texans. And Army veteran Michael Lynch is raising money for the Fisher House Foundation, which helps families of service members who are recovering from wounds or illness.
The marathon attracts prime athletes, but also people who find running helps them battle serious challenges - bipolar disorder, addiction, or sexual abuse. The official charities run the gamut from Alex's Lemonade Stand Foundation to the Delaware Riverkeeper Network to Minding Your Mind, which encourages teenagers who need help to seek treatment.
Duchman works in Center City for the federal Labor Department, handling employment and training grants. She's raising a 5-year-old son, Madden.
She grew up as a bookish child in Hughesville, Pa., near Williamsport. In high school, she noticed she could be physically lazy, not wanting to run with the rest of the soccer team. She didn't like that about herself.
"I decided, 'I'll join the Army. I'll force myself out of my comfort zone.' It was going to help pay for college, get me out of a small town."
She joined the Virginia National Guard and at age 18 went off for basic training at Fort Leonard Wood, Mo.
Twelve years ago she was enrolled at Old Dominion University when the planes hit the towers and everything changed.
After being called up for active duty in Washington, her unit arrived in Iraq in April 2003. Her 266th Military Police Company was assigned to the Abu Ghraib prison, later infamous as the site of inmate abuse and torture.
People still ask her, "Is she in the 'thumbs up' photographs?"
In fact, Duchman said, Abu Ghraib was a large complex, and she was as surprised as anyone after returning home in April 2004 to see the prison at the center of an international scandal. What she experienced, she said, was mortar fire - 30 or 40 attacks a day.
"There were nights it was never-ending," she said. "I just slept in my flak vest."
Soldiers were wounded. Some died. It was hard to be in Iraq. And hard to come home, to be ousted from a life where every decision - when to sleep, when to eat, what to wear - was dictated by others.
"I struggle with it every day," Duchman said. "A lot of things happen when you're gone. My brother was killed by a drunk driver when I was gone. My family was changing. But they were changing without me, and I was changing without them. That was 10 years ago, and we're still working our way through it."
She tries to run every day, in Old City, across the Benjamin Franklin Bridge, by the Delaware River piers, along the Schuylkill. She doesn't have a training schedule. She just runs.
She ran in the half-marathon for the first time last year, and this year wants to improve on her time of 1 hour, 58 minutes.
"My personal goal for this marathon is to enjoy it as much as I enjoyed the first," she said. "To be really happy and enjoy being around everyone like last year."