In which country are the Painted Hills located?

Bob, The Painted Desert is in Arizona, east of the Grand Canyon

The Badlands of South Dakota are also colloquially known as "The Painted Hills"; and vice versa, The Painted Hills in Oregon are also known as "The Badlands". Neither to be confused with The Painted Mountains in Arizona.

Been there. Enjoyed it. Wish I had had more time to explore more.

I live in Oregon but have not seen this natural or many other interesting things in this state.

There are painted hills in many places. This question should be more specific.