The entire length of Lake Shore Drive was shut down to vehicular traffic by 5 a.m. and open to approximately 20,000 bike riders who could choose between the north path or the south path.
The paths total 30 miles with the northbound turnaround at Bryn Mawr and the southbound turnaround at 57th Street.
Sunday marked the 12th annual Bike the Drive event, which last about five hours.
"It is a nice way to take advantage of the lakefront," said bike rider Crystal Quarles. "You can take in the scenery without worrying about collisions and, you know, nasty drivers."
Some participants were choosing to go for a couple of miles and turnaround, while others biked the whole Drive.
Organizers said they would shut down the pathways for bike riders at about 9:30 a.m. The event was scheduled to wrap up at 10:15 a.m., followed by an after party.
The event raised money for the Active Transportation Alliance, which promotes biking, walking, and public transportation use across the Chicago area.