The mother of my child says she is going to leave the state with our daughter. Can I stop her?

Do you have joint custody? Do you have visitation? Are you current with child support?
Were you married to this woman and there is a divorce decree stating that she cannot take your child outside the state without your permission?

When you talk to a Family Law attorney, those are some things you will be asked. It is best to contact an attorney whose practice is Family Law. That person can best advise you and help you pursue this.

Are you or were you married to the mother? If not have you established paternity? These are VERY important things and change what rights you do or do not have.