Mountain lion struck and killed on Interstate 88 in DeKalb County

Illinois State Police said a mountain lion was struck and killed Sunday night on Interstate 88 in DeKalb County.

According to state police, troopers responded to a call of a car accident involving a deer on eastbound I-88 near milepost 104.25. When troopers arrived at the scene, they discovered the animal was not a deer, but a mountain lion, state police said.


None of the occupants of the vehicle were injured in the accident, according to officials.

Experts believe the mountain lion may be the same one that was captured on a trail camera on private property in Whiteside County in late September, the Illinois Department of Natural Resources said in a statement.

(Illinois State Police)

According to the DNR, the animal's body was delivered to the University of Illinois Champaign-Urbana for a full necropsy. The analysis will provide valuable information to biologists about the animal, where it came from and where it traveled across the Midwest.

The DNR said it has been monitoring another reported mountain lion in western Illinois in early October. The animal has a GPS collar that was originally attached in November 2021 by the Nebraska Game and Parks Commission as part of an ongoing research project on their mountain lion population. The animal recently made its way eastward across Iowa and into Illinois, and wildlife officials will continue to monitor its movements while it remains in the state.

Cougars, also known as mountain lions, were extirpated from Illinois before 1870, but have been protected by the Illinois Wildlife Code since 2015. Although extremely rare, mountain lion sightings have been confirmed in Illinois over the past few decades, typically originating from a population in the Black Hills of South Dakota, the DNR said.

The DNR said it's very rare for a mountain lion to pose a threat to people or property, but if you do encounter one that doesn't immediately flee, you should stand tall, wave your arms, throw stones or other objects and yell. The DNR encouraged people not to run, but to slowly back away from the site while keeping an eye on the animal.

The public can report large carnivore sightings at

Editors Note: An earlier version of this story erroneously stated the accident occurred in Kane County.