N.Y. County Law § 216
The board of supervisors shall have power to select and change the site of any county office or building within the county except as hereinafter provided. No site or location for any county jail shall be selected or acquired by such board of supervisors which shall not have been approved by the state commission of correction. No courthouse, civil office of the sheriff, office of the county clerk, county treasurer, clerk of the board of supervisors or board of elections, now or hereafter located in a city or village, shall be removed beyond the limits of such city or village without the approval of a proposition therefor by the affirmative vote of a majority of the qualified electors of the county voting thereon at a general or special election. The clerk of the board of supervisors shall cause a notice of such election to be published in the official newspapers once a week for six weeks previous to such election; and shall on or before the first day of publication cause such notice to be posted upon the bulletin board at the office of each city and town clerk in the county. The notice shall state the time of the election, the name of the office or building and the proposed site thereof by a description in general terms sufficient for readily identifying the proposed site. The clerk shall cause a certificate to be filed with the board of elections stating the proposition to be submitted on or before the first publication. Nothing herein shall be deemed to dispense with any required approval of a site or building by any state officer or department. In the event the board of supervisors proposes changing the present site or sites, as the case may be, of two or more of the above specified offices or buildings from their present site or sites, as the case may be, to one site, such proposal may be contained in one proposition without the necessity of allowing a separate vote on each of the offices or buildings concerned, and in such case, the proposition and the notice of such election shall state, as to each office or building affected, the name of the office or building, the present location thereof by reference to the city or village, as the case may be, and the proposed site thereof by a description in general terms sufficient for readily identifying the proposed site.
N.Y. CountyLaw § 216