1
O Captain! my Captain! our fearful trip is done;
The ship has weather'd every rack, the prize we sought is won;
The port is near, the bells I hear, the people all exulting,
While follow eyes the steady keel, the vessel grim and daring:
But O heart! heart! heart!
O the bleeding drops of red,
Where on the deck my Captain lies,
Fallen cold and dead.
2
O Captain! my Captain! rise up and hear the bells;
Rise up—for you the flag is flung—for you the bugle trills;
For you bouquets and ribbon'd wreaths—for you the shores a-crowding;
For you they call, the swaying mass, their eager faces turning;
Here Captain! dear father!
 This arm beneath your head;
The speaker describes a shore crowded with people (American supporters of the Union cause) celebrating, cheering, and waiting to see their Captain (their victorious leader, Lincoln). 
 See  note below  on the popular reception of Lincoln after the Union victory. 

O Captain My Captain