Can I get custody of my niece?

My niece is living with her mother and her boyfriend( which shes not suppose to be around) and her Grandmother. They are all unfit. None of them work they are living off of system and they hardly have to pay for anything. Her father was recently arrested and is doing 4-11. (shes not suppose to be around him either) I'm not married but neither are her parents nor her Grandmother that took her in. Does it make a difference? Do I have to be married to take her?

They're not unfit until a court says so. Has one?

Flower, if the chid s in danger, call "911".
If you believe the chid is being neglected, call "911".
As far as adoption ges, anything can happen.
But, there are many people in line ahead of you, if adoption or custody battles begin.