Where had the ship been? Why?

In his famous poem "O Captain! My Captain!" Walt Whitman uses an analogy to lament the assassination of President Abraham Lincoln. Lincoln is the captain of the ship (that is, the ship of state) who now "lies fallen cold and dead" on its deck. Several phrases in the poem refer to where the ship is during the moment of the poem and where it has been. First, Whitman writes, "our fearful trip is done." This refers to the end of the Civil War, which occurred on April 9, 1865, when Robert E. Lee surrendered. Just five days later, Lincoln was assassinated.
Whitman also writes, "the ship has weather'd every wrack, the prize we sought is won." This refers to the four long years of fighting that wracked the country during the Civil War. Lines in stanzas 1 and 2 describe a celebration: bells, bugle trills, waving flags. This is probably a reference to Lincoln's second inauguration, which occurred on March 4, 1865, a month before the end of the war. Lincoln had carried all but three states in the election, and with the sense that the war was nearly over at last, the festivities were happy and hopeful. The following line certainly describes the huge crowds that thronged to the inaugural celebration: "For you they call, the swaying mass, their eager faces turning."
The poem is made all the more poignant by the contrast of the recent celebration and victory with the cruel murder of the man who led the country through such a horrible ordeal.