The Appalachian trail is pretty great!

John Muir

Foothills Trail on the NC/SC border through the Blue Ridge Mountains, I believe it is possible to connect to the Appalachian trail now for longer hikes all the way up the east coast.

The favorite one I’ve actually hiked is the River to River trail in southern Illinois. The fact that it’s the only one I’ve hiked might have something to do with that, though the eastern half is pretty darned scenic (especially for a midwest trail).