N.Y. Gen. Mun. Law § 703-a

§ 703-a. Resolution by governing boards of municipalities to initiate\nannexation of territory. Except for territory proposed to be annexed\nwhich is entirely uninhabited or territory in an agricultural district,\nor outside of such district but eligible for an agricultural assessment,\npursuant to article twenty-five-AA of the agriculture and markets law,\nthe governing boards of two or more municipalities which have mutually\nagreed to study the annexation of territory, may, by joint resolution,\npropose the annexation of such territory, pursuant to the provisions of\nthis article.\n