Pilar, Buenos Aires

Pilar
City
Nuestra Señora del Pilar
Pilar Location in Greater Buenos Aires
Coordinates: 34°27′S 58°55′W / 34.450°S 58.917°W / -34.450; -58.917
Country	Argentina
Province	Buenos Aires
Partido	Pilar
Government
• Mayor	Federico Achával (PJ-UP)
Elevation	18 m (59 ft)
Population
• Estimate  (2022)[1]	52,000
CPA Base	B 1629
Area code	+54 2322

Pilar is a city in Buenos Aires Province, Argentina. It is part of the Greater Buenos Aires urban conurbation and is the seat of the administrative division of Pilar Partido. It is located about 51 km northwest of downtown Buenos Aires. As of the 2022 Census, the city had a population of nearly 52,000.

Originally located on the flood-prone banks of the Luján River, the small town of Pilar and its chapel were relocated to their current site in the 1800s. Pilar was the site of the signing of the Treaty of Pilar in 1820, a foundational document that is one of "pre-existing pacts" of the Constitution of Argentina and laid the foundation for Argentina's federal system of government.

Since the 1990s, Pilar has undergone a demographic transformation fueled by the development of gated communities within and around the city limits. In recent decades, as the administrative center of Pilar Partido, the city has diversified its economy, supported by neighbouring industries and a growing service sector in the district. As a result, Pilar has solidified its position as a development hub on the outskirts of Greater Buenos Aires.