N.Y. Uniform Dist. Ct. Act § 2402
The district court system of Suffolk county shall be established on the first day of January next succeeding one year from the general election at which at least three contiguous towns, by a majority vote cast in each such town, elect to participate in and become a part of such county district court system. The election of any such town shall be irrevocable. The town of Shelter Island shall be deemed to be contiguous to the towns of Southold, Southampton and East Hampton. Once the district court system of Suffolk county has been created, any town contiguous to such district may thereafter elect at a general election to become part of the district court system, which referendum shall be initiated by town board resolution, and upon making such election by the majority vote of the electors of such town, such town shall become irrevocably a part of the county district court system on the first day of January of the second year following such election.
N.Y. Uniform District Court § 2402