A gaily dressed and gallantly singing knight has searched day and night for Eldorado, but as time passes, he grows older and more melancholy because he cannot find it. As he loses his strength, he asks a "pilgrim shadow" of Eldorado's whereabouts, and the shadow replies that he must go "over the mountains of the moon" and "down the Valley of the Shadow" to find Eldorado.
According to legend, El Dorado is a city of gold and unimaginable wealth, and it derives its name from the Spanish word for "golden." Historically, the rumor of this mystical city hiding somewhere in South America has sparked a number of futile quests among the Spanish conquistadors of the sixteenth century. Notably, Gonzalo Pizarro and Francisco de Orellana led an expedition in search of the spices and gold of El Dorado, but the voyage ended in disease and hunger, although Orellana eventually discovered the Amazon River. Other searches for the city were similarly unsuccessful, and Poe indirectly alludes to this history of El Dorado in his poem by referencing its famous inaccessibility.
Structurally, "Eldorado" consists of four stanzas, each of which consists of six lines. The first stanza describes a "gallant knight" who is "gaily bedight" and in the high point of optimistic youth, as he believes unswervingly that Eldorado exists and that he will eventually locate the city. The second stanza is less bright in tone, as the knight moves on to old age and begins to suspect that he will never achieve his life's goal. The next stanza then brings him to his deathbed, as he asks the "pilgrim shadow" for advice in much the same manner as the narrator of "The Raven" asks the raven for advice about his lost Lenore and about life after death. Finally, the last stanza moves from life into death, completing the human life cycle as the shadow advises that the knight continue his quest into death.
If the search for Eldorado is an allegory for the progression of a lifetime, then the fact that the search only ends in death may have multiple meanings. Some critics have described the knight's quest as indicative of faith that fulfillment exists after death, a sentiment echoed by Guy de Vere of Poe's poem "Lenore." In addition, Poe's works have often associated death with ideals of purity and beauty made permanent, again as in "Lenore" or in his short story "Ligeia." Poe may also be characterizing life as a constant search, to which the object of search only appears in death, an interpretation that recalls the narrator of the short story "MS. Found in a Bottle," who learns not to fear death in hopes of achieving knowledge.
Although the knight's journey in "Eldorado" may be essentially positive in that the knight is guaranteed an end to his quest, we can additionally interpret his death as an expression of futility and age. As in his poem "The Bells," each stanza furthers the inevitable movement of life toward death, and despite the knight's many efforts, he is unable to achieve his goal except through the end of life. The protagonist's seeking of wealth is echoed in Poe's story "The Gold Bug," but where the characters in "The Gold Bug" redeem their fortunes by finding a buried treasure, the knight of "Eldorado" sees his strength fail first. Poe himself often had fiscal troubles, and such an end to his pursuit of financial stability may have appeared disastrous to him.
The lines of "Eldorado" are individually very short and display no particular rhythm, but the rhyme scheme for each stanza consists of two groups of three lines. The first group is a couplet followed by a line ending in the word "shadow," while the second group consists of a couplet followed by the end rhyme of the word "Eldorado." Foreshadowing this refrain is the alliterative phrase "in sunshine and in shadow," which establishes the main contrast of the poem between shadow, which is later personified as an aspect of death, and Eldorado, which is associated with light. The two words and ideas interact throughout the play, and by the end of the poem, they combine in the directions of the "pilgrim shadow," a phrase that further highlights the connection between the knight's wanderings and his death.