N.Y. Real Prop. Tax Law § 902

§ 902. Lien date. The amount of all taxes, special ad valorem levies\nand special assessments levied upon any parcel of real property by the\nboard of supervisors shall, except as otherwise expressly provided by\nlaw, be and become a lien thereon as of the first day of January of the\nfiscal year for which levied and shall remain a lien until paid.\n