Hmmm those are tricky to distinguish. A region is a broader scale. Example: “The Midwestern region of the United States is pretty.”
An area is usually used to describe a smaller place or piece. Example: “The area around my road is covered in trash.”
But you're right. Area and region mean the same thing basically. In spoken English, it doesn’t matter which one you use. If it’s for something more professional or academic, though, I would use the word "region."