"This Land Is Your Land"
the imagery in the first few stanzas uses imagery to describe the things that he sees as he takes this figurative journey throughout the great land, the  United States, and this is the part that most people remember and know the best.
       "From California to the New York island"
which is an illusion to Ellis Island, where most immigrants entered the country with the promise of open space, a place to work, and a better life. however, later in the song, it talks about the prejudices that people ended up bringing with them and what that would mean for someone living in the US.
      "as I was walking, I saw a sign there
       and on that sign there, it said 'no trespassing'
       but on the other side it didn't say nothing
       this land was made for you and me"
but still, this land is my land, and this land is your land, as the chorus repeats. even if there are problems with this land, the intention in the beginning is good.
is that always enough?