Legal Question in Real Estate Law in Illinois

This is known as an "encroachment." You can address this issue by filing a lawsuit against the adjacent property owner to fix or repair the retaining wall. Please note that if you let the situation go on for too long, the adjacent property owner may develop certain rights to the portion of your property where the encroachment occurs. I recommend addressing the issue sooner rather than later. If you are interested in discussing the encroachment please reach out to my firm and we can assist.