A place that haunts someone is one they visit often because it reminds them of something important or painful from their past.
When people say something "haunts" them, they usually mean that it's a memory or situation that keeps coming back into their mind. It could be the house where they grew up and had happy times with family, but also experienced some sad events. Maybe you know someone who visited the city where they used to live, and now they can't stop thinking about all the good (or bad) memories it brought back. Sometimes haunts are connected to a place or situation, but often it's just something that keeps popping up in their thoughts.
A place at which one is regularly found; a habitation or hangout.
Example: I went back the town I used to live and visited all my old haunts.
To inhabit, or visit frequently (most often used in reference to ghosts).
Example: A couple of ghosts haunt the old, burnt-down house.
