The final 6,000 combat troops will leave over the next few weeks. That means about 50,000 soldiers will remain in Iraq mainly as a training and security force.
Members of the 4th Stryker Brigade reflected on the historic moment.
"You think before you come here that you're an adult, you're a grown man, but this place will change you," Sgt. Terry Wetzel said. "I've seen some friends die. I've been right there and had to carry the bodies."
When the brigade left, it fulfilled President Barack Obama's pledge to end the U.S. combat mission in Iraq by the end of August.
"We put in our blood, sweat and tears since we've been here for 12 months," Spc. Don Lanpher said. "We know we did our jobs. We know it's not going to be in vain."
Jim Bright and wife Jane of Newbury Park understand the price of the war in Iraq. Their son was killed in action in 2003.
"There's 50,000 or 500,000 who are going to be there probably forever," Jane Bright said.
The couple thinks the focus should now be on helping veterans once they come home.
"When they come back after those experiences and are asked to be integrated into a normal society, it's impossible without having a lot of assistance, a lot of guidance, a lot of counseling," Jim Bright said.
According to the Pentagon, the U.S. death toll in Iraq stands at 4,415.