The Dreadhead Cowboy, a local celebrity whose real name is Adam Hollingsworth, said he rode down the Dan Ryan Expressway in support of the #KidsLivesMatter movement.
The initiative aims to raise awareness and motivate residents to fill out the US Census to help communities receive better funding.
Hollingsworth was taken into custody by Illinois State Police. CNN has reached out to the state police for comment.
In the video posted to Facebook, Hollingsworth is seen riding down the expressway, seemingly with a motorcycle escort, and yelling “Kids Lives Matter.”
The horse was taken into police custody by the Chicago Police Department, and videos posted to social media showed the horse being loaded into a Chicago Police Mounted Patrol Trailer.
Officers will be transporting the horse to Animal Care and Control, CPD told CNN.