The speaker seems to be remembering a woman, Lenore, who is now dead or lost, and the act of writing is his way of keeping her. He says he wrote "against night and forgetting," as if the poem were a small lamp held up to the dark. The phrase "still as thought" is lovely and odd: she is quiet, but not empty, as though stillness were a kind of thinking.
The scene that follows is strange and gentle. A "plain dinner among the graves" suggests a meal shared with the dead, or at least beside them, with no fuss and no fear. The final image, the hill sleeping "in the manner of cut stone," makes the landscape feel calm but also heavy and permanent, like a monument. The mood is hushed, tender and a little solemn. Grief here is not loud. It sits quietly, eats simply, and keeps watch, while the poem itself tries to hold on to what time would erase.