Some are celebrating the holiday with elaborate house displays.
The Roseland Community Hospital hosted a trunk or treat event from 4 p.m. to 6 p.m. outside at the parking lot on 111th Street.
The city of Aurora hosted a big event from 3-5 p.m. at Wilder Park. The mayor was there, along with firefighters, police officers and other staffers to hand out candy.
At 3 p.m., Englewood's 7th District police held a Halloween fest, running until 6 p.m. at the Englewood Police Station on 63rd Street.
Naperville hosted its Halloween in the Park from 1-1:45 p.m. It took place at 95th Street Library Wagner Pavilion, 3109 Cedar Glade Drive.
The South Shore hosted its Hallowhood Night, with Halloween activities including pumpkin painting and a "House of Horrors" and a stepper's set. The Community crawl took place from 3-9 p.m. along the 71st Street corridor The event is organized by Alderman Desmon Yancy, Lost Boyz Inc. My Chi, My Future, South Shore Works, CPD, Chicago Park District and others.
UCAN hosted a free "Trunk or Treat" event for kids of all ages and families on the West Side. The event will feature arts and crafts, laser tag, horse rides, free costumes, face painting and food. It began at 4 p.m. on UCAN's Drost Harding campus at 3605 W. Fillmore St.
A house in Buffalo Grove is celebrating Halloween in a big way. Rick Tadelman spends a couple months putting a display together in his yard every year, and he has done so for over three decades.
"When I have the Halloween display on at night and people come and visit, the adults like it just as much as the kids," Tadelman said.
Every year, Tadelman adds a few more features. He estimates there are about 200 features in his yard, including plenty of pumpkins. He's got a few skeletons in and out of his closet. It takes up his entire yard and garage.
He's started to use a little space belonging to his understanding neighbors. Next-door neighbors Bill and Tricia Ballad have had to buy more candy to accommodate the huge crowds that show up on the block every year. Last year, they went through about 30 pounds.
"In the past, we'd get 30-40 kids before we lived next to Rick. So it's significantly more," Bill said.
Tadelman said he's lost track of how much he spends on this display, but it's a lot. He does it at his own expense, though he does have a collection bowl to raise money for charity.
Aside from the spooky characters, Halloween is also about the trick-or-treating, and Tadelman has that covered pretty well. He's got an assortment of full-size candy bars to hand out to the older kids, and smaller selections for the younger ones, as well as gift card for a free ice cream at Culver's.
For Tadelman, Halloween is the best day of the year.
"Halloween is just a fun holiday," he said.