If you dream of being in frontier, then such dream denotes to variety in your waking life. Perhaps you are going through new phase of your life and gaining the knowledge to different things such as who you are and what you are able to achieve.
Dream dictionary: Frontier dream meanings
It symbolizes the separation between two worlds, between two stages of life. Frontier is also an omen that we are approaching a crucial point of our life in which the orientation of our desires and ambitions will change.