Way Station by Clifford D. Simak

Enoch Wallace survived the carnage of Gettysburg and lived through the rest of the Civil War to make it home to his parents' farm in south-west Wisconsin. But his mother was already dead and his father soon joined her in the tiny family cemetery. It was then that Enoch met the being he called Ulysses and the farm became a way station for space travellers. Now, nearly a hundred years later, the US government is taking an interest in the seemingly immortal Enoch, and the Galactic Council, which set up the way station is threatening to tear itself apart.