What is the setting in the poem, O Captain! My Captain!?

The immediate setting of O Captain! My Captain! is the ship under the command of the speaker’s Captain. Beyond the ship, the shore is filled with a celebrating crowd. This spatial divide emphasizes the differences between the general public excitedly awaiting the arrival of the Captain and his ship on shore and the intense grief of the speaker on the ship. The ship, still out at sea, isolates the speaker and his Captain from the crowd. While the crowd on shore is joyful about the imminent return of the ship and blissfully unaware of the tragedy that has occurred aboard, the speaker’s placement on the ship allows him to have prior and up-close knowledge of the painful reality of his Captain’s death before everyone else.