I know you can see Mount Rainier from Mary's Peak outside of Corvalais, which is 295km away. And I mentioned it in another comment here, but standing on paulina

I know you can see Mount Rainier from Mary's Peak outside of Corvalais, which is 295km away. And I mentioned it in another comment here, but standing on paulina peak on a clear day, you can see both Mount Adams and Mount Shasta, more than the entire height of Oregon.