How does an administrator of an estate without a will officially terminate their duties when the estate is settled?

That would vary from state to state. ===Texas=== Texas: dependent administration: an application is filed. When granted by the court, the duties terminate. Independent administration: duties terminate when an affidavit of completion is filed, or when all of the duties have been completed, whenever that might be. Most independent administrations are not closed in Texas, leaving open the possibility for additional relief from the court should it be needed, subject to a defense of lack of jurisdiction if all of the duties are complete. A good rule of thumb would be when the IRS grants the administrator a discharge of his/her duties, although most administrators do not request it. ===Massachusetts=== When there is proof filed that no state or federal estate taxes are due and the final account has been allowed.