Some 2,000 people, many associated with anti-war organizations, gathered at Michigan Avenue and Congress Parkway to begin their march.
They called for an end to the war in Afghanistan, now the longest military conflict in the nation's history.
"It's time to end the war and bring the U.S. troops home," said Mary Dean of Voices for Creative Non-Violence. Said protestor Keenan Boyd, "I'm here today to support these people. The veterans, the people of the United States that know that these wars are unacceptable."
The anti-war rally then joined forces with the ongoing "Occupy Wall Street" picketers, who were demonstrating along Lasalle Street in the Financial District.