Police and organizers estimated that at least 850,000 participants attended the parade that winds through the North Side including one of the city's gay neighborhoods. The number was far more than the roughly 750,000 people who attended last year.
While the event was mostly celebratory, with 86 degree weather, music wafting off floats and scantily clad dancers shimmying in the streets, participants said it was also an expression of equal rights.
Eldridge Shannon, 19, came to the festivities with his friend. The bisexual teen from Evanston said gay marriage is a serious issue and called efforts against gay marriage irrational.
"I don't understand why everyone isn't in favor of gay marriage," Shannon said. "It's just stupid. If Kim Kardashian can get married for about 70 days, two people of the same sex who love each other should be allowed to do the same."
About a month ago, 25 Illinois couples sued for the right to marry, challenging the state's marriage law, which defines marriage as between a man and woman. However, Illinois Attorney General Lisa Madigan and Cook County State's Attorney Anita Alvarez have refused to defend the lawsuit, saying the state's gay marriage ban violates the constitution. Gay marriage opponents have said they're strategizing over how to intervene.
Advocates have said that they believe the time is right for Illinois to allow gay marriage because the issue appears to be gaining momentum. The state enacted same-sex civil unions last year, recent public opinion polls show that the majority of Americans don't oppose it and earlier this year President Barack Obama's said he supports gay marriage.
The LGBT community wants equal marriage rights, said parade organizer Richard W. Pfeiffer, saying civil unions don't go far enough.
The issue was prevalent during the parade with many people wearing t-shirts that read "Legalize Gay."
The parade was slightly different than years past. It took an altered route to address longstanding concerns about crowds, drinking and transportation access.
Police said there were no arrests or reports of crime related to the parade. Last year parade organizers said vandals had punctured the tires of about 50 floats before the event began, but the festivities went on as planned.
Michigan resident Jordan Martin, 19, wore a T-shirt emblazoned with the words "Kiss Me I'm Gay." She was hopeful that gay marriage will become a reality for all Americans.
"Events like this allow everyone to feel comfortable in their own skin," she said.
The event drew many public figures, including Gov. Pat Quinn and Chicago Mayor Rahm Emanuel, along with families.
Chicago resident Carrie Roberts brought her two children, ages 5 and 6.
"The parade is a good expression of freedom and acceptance," she said. "I thought my kids would enjoy it."
Large-scale pride parades also took place in San Francisco and New York.
Copyright 2012 The Associated Press.