N.Y. Gen. City Law § 141
Whenever a city having a population of more than three hundred thousand inhabitants shall desire to exercise the power conferred by this article it shall through its board of health, select such locality outside of its corporate limits, but within the state, and not within the corporate limits of any other city or any village, as it may consider best adapted by reason of climatic and other conditions for the treatment of such disease, and shall make application to the department of health for the approval of the site so selected. Upon such approval being given the city may acquire title to such lands as its board of health may designate, within the limits of the locality submitted to and approved by the state department of health. The provisions of law relating to the acquiring of private property for public purposes are hereby made applicable as far as may be necessary to the acquiring of title to such lands.
N.Y. Gen. City Law § 141