Can you adopt a 18 year old at Illinois?

Yes, in Illinois, you can adopt an 18-year-old, but the process is different from adopting a minor. Since the individual is legally an adult, they can consent to their own adoption without the need for parental consent. This type of adoption may occur for various reasons, such as formalizing a parent-child relationship or providing legal benefits. However, it's advisable to consult with a legal professional to understand the specific requirements and implications of the adoption process.