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.

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.

The rural outpost that later became Pilar was first assigned a local authority in 1774 with the appointment of Ventura López Camelo as its first alcalde, or mayor.

This Treaty marked the end of the war between the League of Free Peoples formed by the provinces of Entre Ríos and Santa Fe against Buenos Aires.

[3] The Parish of Our Lady of the Pillar was consecrated in 1856, and the partido (county) of Pilar was established in 1864, its first municipal mayor being Tomás Márquez.

He remembers when, in 1729, a local indigenous man exposed to public worship an image of the Virgin in a chapel erected on his property.

In addition to the liturgical activities, including the huge procession with the venerated image stands out, the Municipality of Pilar organized a civic-military parade that the forces of the district, educational, social and sporting institutions, traditionalist centers and schools involved native dances, among other social organizations.

The pact, signed in the original chapel of Pilar by Francisco Ramírez, Estanislao López, and Manuel de Sarratea, ended the war between the provinces of Entre Ríos and Santa Fe against Buenos Aires.

Begun as a simple adobe structure in 1821 under the direction of architect José Villa, the vault of the nave and the upper floors were made from 1840.

The first mass in Pilar was held here, and with the advent of bricks as building material in the 19th century, the old wooden cross was replaced by masonry.

Established on 20 August 2003, the reserve made use of five former military lots bordering the north bank of the Luján River and totals 297 hectares (730 acres).

A series of lagoons make it home to a profusion of roman cassie, Jerusalem thorn, tule, catay, waxyleaf nightshade and other flora, as well weasels, rabbits, nutria, skunks, amphibians, reptiles, and over 60 species of birds.