More than 40,000 runners are expected to take part in this year's race, traveling 26.2 miles through 29 neighborhoods.
Several changes were made to the race course this year. To view the full course map, click here.
Street closures in the Grant Park area began Monday. Balbo is closed from Lake Shore Drive to Michigan Avenue, Jackson Boulevard is closed from Columbus Drive to Lake Shore Drive and Columbus us closed from Roosevelt Road to the Congress Parkway. The Columbus closure will be extended to Monroe on Friday and to Randolph Street Saturday.
For a full list of street closures including race day closures, click here.
Parking restrictions will be in effect along the course and will be strictly enforced, officials said.
CHICAGO MARATHON COULD BE TARGET FOR PROTESTERS
The Chicago Marathon draws runners from every state and most countries throughout the world - and that makes it a potentially attractive target for protesters. Race organizers are taking extra precautions to ensure security.
"This event is a celebration of humanity. It's about emotion. It's an event that allows individuals to express themselves and it's an event where people come together," said marathon director Carey Pinkowski.
But it also comes at a time where racial tensions are high in anticipation of a verdict in the murder trial of former police officer Jason Van Dyke for the killing of Laquan McDonald.
Protesters have recently targeted large city events, like shutting down Lake Shore drive before a Cubs game, among other actions. And several have talked of targeting the marathon because of its city-wide course and worldwide audience.
One group of five men have run every previous Chicago marathon and plan to be at the starting line this year. They've run after 9/11 when security was incredibly tight, and they've run after the Boston Marathon bombing when security was even more tight. They are aware of the possibility of protests this year, but also focused on the task of running a marathon.
"I think people are more worried that they have been in other years. You think about it once in a while. But mostly you're focused on the next mile or the next water stop," marathoner Henry Kozlowski said.
The marathon attracts runners from 140 countries and more than 1.5 million spectators on a course that runs through numerous neighborhoods on the North, South and West sides.
Much of the visible security has been focused on the finish line in Grant Park. But Pinkowski said security will be in place throughout the course.
"I'm confident in our partners in the Chicago Police Department, our federal agencies and the resources we have," Pinkowski said.
The only interruption in the 40-year history of the Chicago Marathon was caused by hot weather. The weather forecast looks pretty good for runners this year. Race organizers say they are looking forward to a great day with no disruptions from protesters.