The Kankakee County Sheriff's Office said the person was found inside a damaged home on Oakwood Drive in Aroma Park.
The person appears to have been a victim of the tornado damage, the sheriff's office said. Their identity was not immediately released.
The victim's next-door neighbor told ABC7 that a crew was clearing debris off of his roof on Thursday afternoon when they spotted his neighbor inside his home.
"The whole thing we were all holding on to was, even though our houses are damaged, everybody was OK. So, the fact that our neighbor isn't OK, that's hard," said Tom Ascher. "He was a nice guy. He was very quiet. We interacted a few times as we were working on each other's yards, always nice to me, my family. Always called me 'young man.'"
Ascher says a large tree limb had fallen into his neighbor's home.
One stretch of homes in Aroma Park was completely flattened by the tornado, which was on the ground for over an hour on Tuesday.
A woman who lived in one of the homes hit was found under the rubble. She has been hospitalized for her injuries.
This news comes as another round of possibly dangerous high winds is expected to sweep through the already devastated area.
"I know they're just things, but you just don't expect this happen to you and when the tornado passed over our house, it was terrifying," said one resident named Ann.
Roy Bernard and his wife, Ann, had three trees fall onto their house and demolish their cars and garage. Now, the couple are concerned about the impact of this next round of strong winds.
"Were just kind of hoping that the structure damage isn't bad enough to cause the thing to collapse. I mean, that's the biggest thing right now," Bernard said.
Brandon Tomblin has lived in Aroma Park for about 40 years.
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Never did he imagine he would be rebuilding his home after a tornado swept through on Tuesday, leaving behind a trail of devastation. His personal belongings were strewn across his neighbors' yards.
"It's half the house. It's the whole garage, half the kitchen, living room. Windows are blown out," Tomblin said. "My wife walked down here because my car got shattered. She called me crying, that our garage was gone."
Kankakee County and other parts of the Chicago area will be under a High Wind Warning from 1 a.m. to 4 p.m. Friday. On Thursday afternoon, Tomblin's family rallied together to cover the roof.
"With the winds coming in tonight and tomorrow, I want to get the tarp down and secured, so it don't rip anything off or debris doesn't blow in the house," Tomblin said.
This comes as the community is trying to recover from Tuesday's events.
Illinois Gov. JB Pritzker was with emergency teams visiting Kankakee County on Thursday. The governor was briefed by the Illinois Emergency Management Agency before assessing the storm damage for himself.
"There were 30 homes, maybe more now, that have been totally destroyed," Pritzker said. "I know that we as a state, we're going to do everything that we can with our resources to help, and then, I expect the federal government to do its job."
Pritzker said the state would do a thorough damage assessment before reaching out to FEMA for federal assistance.
"I've directed my teams to provide the full assistance the of the state of Illinois to the people of this region," Pritzker said.
A lot of windows have been boarded up, and tarps have been placed on roofs. Crews have also been clearing out debris.
With wind gusts up to 150 mph, homes along Sandbar Road were decimated on Tuesday.
The ground around what was a two-story home was left covered in debris, including clothing, a mattress and an office chair. A life's worth of memories and belongings were strewn about in a matter of minutes.
"Two-story home right here, four-car garage right here, we don't have anything, gone," homeowner Sam said.
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Sam said he wasn't home at the time. He lives in the Chicago suburbs and bought the property as a retirement home. He is devastated and in disbelief, he says, by the loss.
"I bought this home a year ago," he said. "I've been working on it, and it should be our retirement home. Our life savings in this house, gone in 10 minutes."
His neighbor, however, a woman who lives alone, was home on Tuesday evening. She was later found trapped underneath the rubble, he says, after the storm.
"Her brother told me they found her," Sam said. "She's in the hospital with some broken ribs. She's banged up. I know that her kids were walking around the rubble looking for the cats. They found one dead."
This is just one of the areas with extensive tornado damage. Dozens of repair crews were dispersed across the county on Thursday morning, navigating scattered debris, downed power lines and uprooted trees.
Highway 45 and River Road, along the Kankakee River, and Waldron Drive are all areas hard hit, with homes destroyed.
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Over at Grace Baptist Church in Kankakee, the building has been turned into a disaster relief center. Resources are available at the church, which opens at 8 a.m., according to their Facebook page. Families have been stopping by to get water, food, diapers, clothing, and other supplies for cleanup.
"People from the community are bringing their kids here, kind of a relief from all the work they're doing," said Grace Baptist Church Pastor Chad Dalton.
For those who have been impacted by the tornado, they say any little bit of help goes a long way.
"A lot of people don't have help nowadays, you know, so, it's a blessing that they can come together and help the community out," said Kankakee resident Shequitta Woodard.
There has been an overwhelming show of support for people impacted by the storm, with a Red Cross shelter stationed at the Kankakee Community College.
Volunteers, local business and community organizations have been making sure food is available for neighbors, first responders and crews working to clean up and bring some semblance of normalcy to this devastated community.
School District 111 schools remain closed Thursday. The district is also offering free breakfast, lunch and dinner. The meals are served at the Lincoln Cultural Center on Warren Avenue in Kankakee.
Homeowners are out salvaging what belongings they can and coming to grips with what lies ahead. Sam said he will rebuild his dream home, no matter how long it takes.
"I've done construction all my life, but I don't know where to start honestly. I don't know," Sam said.
Families ABC7 has been talking to say it is going to be a while before Aroma Park returns back to normal. Grace Baptist Church says they will be welcoming community members in need of help or a meal through the weekend.