How long does a parent have to be absent for it to be considered child abandonment?

For purposes of termination of parental rights (other than by mutual consent), the abandonment can be shown in about a dozen different ways. If the question is the most straightforward one, of leaving the child with anyone (including the other parent) for six months or more without any attempt to visit or communicate, that's the period of time necessary. But, in law there are generally details and exceptions, as there are in the abandonment statutes. For example, the 6-months period does not include any time the parent is prohibited from visiting or contacting the child by a court order. And the statute sets out various defenses. If you are considering petitioning for termination of parental rights of the other parent, I strongly suggest you contact an experienced family lawyer. Such people can make complex matters much simpler. Good Luck.