This article deals with the question of the necessity for delimitation of the St. Petersburg metropolitan area, for research on unrelated to the administrative division data. Based on the analysis of existing options for boundaries, the choice is made in favor of a synthetic delimitation, based on the delimitation from the materials on justification for the master plan of 2005 and the author's additions. This version of the agglomeration borders is not related to the boundaries, has several belts, including the author's. However, the aspect of agglomeration sectorality is not taken in this variant.