I have drove in 49 out of 50 states (never been to Hawaii) and Illinois ranks the worst in my opinion. It’s like they ran out of asphalt and stopped doing any repairs 10 or 20 years ago.
To people not living in the U.S., feel free to complain about your country’s roads too.
I haven’t been on the road a ton in recent years, nor have I driven every state, but I have driven at least some in every state from Vermont to Florida, across the entire American southeast, and down I-10 to California. In my experience, Louisiana was the worst.