If a 16-year-old runs away from their custodial parent to live with their non-custodial parent can they be forced to return home?

Yes they can. Depending on what state you are in, the legal age has changed from 18 to 17. 17 year olds are considered an adult in Georgia. Not sure of any other state, then they can do what they want. Not in the sense that the police can come and take the minor into custody and return them to the custodial parent. Before action can be taken the custodial parent will either need to file a report with the police that the child is a victim of parental abduction (it is not relevant if the child went willingly). Or the custodial parent will have to file a petition with the court to have the child returned to their custody, in which case the other parent will likely be charged with a contempt of a court order. In regards to Georgia amending the age of majority law to seventeen, that is not quite correct. Georgia has taken the same action that several states have, in that they have amended the juvenile code to designate a seventeen years old as an "adult". This gives the court the power to have said "adult" adjudicated on the same level for most criminal infractions. It also gives the court the power to grant early emancipation rights to those individuals who meet the specified criteria. Therefore, the actual legal age of majority still remains at eighteen (18).