N.Y. Gen. Mun. Law § 210

§ 210. United States may acquire land in cities. The United States is\nhereby authorized to acquire by condemnation, purchase or gift in\nconformity with the laws of this state, one or more pieces of land not\nexceeding two acres in extent, in any city or village of this state, for\nthe purpose of erecting and maintaining thereon a public building for\nthe accommodation of post-offices and other governmental offices in any\nsuch city or village.\n