Dropdown with additional information

I have a drop down list with counties that I want my user to select from. The county list has many counties from many different states. The problem I am having is that when I load the drop down list with the counties, the duplicates show up but I have no idea which state they belong to.

Is there a way to resolve this?

I saw this post that could offer a solution but it never got a answer.

How are you folks managing this type of use case?