1- To dream of crossing a border or frontier from one placc to another represents making great changes in life, actively instigating a change from one state to another, perhaps taking ourselves from the past to the future, or causing other people round us to make those changes.
2- Psychologically when we cross from one way of life to another such as changing from puberty to adulthood or from middle age to old age we need to depict this by creating an actual marker. In dreams for a frontier to appear is crossing a barrier within ourselves.
3- Spiritually, we have a new experience ahead of us which we can use on our way towards enlightenment. [1]