N.Y. Fam. Ct. Act § 472

§ 472. Undertaking to be filed. If the property securing the\nundertaking consists of real estate, the undertaking shall be filed with\nthe county clerk of the county in which the real estate is located and\nthe same shall constitute a lien upon the real estate specified in the\nundertaking. The county clerk of each county is hereby directed to\naccept such undertakings for filing and to provide proper and sufficient\nbooks and indexes wherein the same shall be entered.\n