 Established on 25 October 1878 (provincial law 1244), Marcos Paz is at the eastern border of Greater Buenos Aires with the rest of the province, although in an administrative sense, it is not considered part of the metropolitan area.According to the 2001 INDEC National Census, the "partido" has 43,400 inhabitants, and a population density of .Marcos Paz's mayor is Ricardo Pedro Curuchet, of the local "Partido Vecinalista".