'Eldorado' was first published in Flag of Our Union (21 April 1849). The text used here is from the Griswold edition.
Eldorado Gaily bedight, A gallant knight, In sunshine and in shadow, Had journeyed long, Singing a song, In search of Eldorado. But he grew old - This knight so bold - And o'er his heart a shadow Fell as he found No spot of ground That looked like Eldorado. And, as his strength Failed him at length, He met a pilgrim shadow - 'Shadow,' said he, 'Where can it be - This land of Eldorado?' 'Over the Mountains Of the Moon, Down the Valley of the Shadow, Ride, boldly ride,' The shade replied, - 'If you seek for Eldorado.'