N.Y.C. Admin. Code § 2-203: § 2-203 Power to mark boundaries and to make surveys.

The mayor shall have the power to direct the president of any borough to mark any boundary line or lines of the city, as such boundary line or lines is or are determined in and by the code, so as to distinguish and define the boundaries of the city, the boundaries of the boroughs, and any other boundary line or lines determined in and by the code, by such monuments as may be authorized by the mayor.