According to Wikipedia:
"Pilar is a city in the province of Buenos Aires, Argentina, and the head
town of the partido of the same name. It has a population of more than
230,000 inhabitants as per the 2001 census. Pilar is the site where the
Treaty of Pilar was signed on 1820-02-23, establishing the basis for
Argentine federalism. Because of this relevant event, the city of Pilar is
acknowledged as the "Cradle of National Federalism". This Treaty marked the
end of the war between the provinces of Entre Ríos and Santa Fe against
Pilar has experienced a huge demographic expansion, specially
in the last decade, that brought with it both a great economical increase
and the rapid development of a prominent city. The city is also known as
being an exclusive residential hideaway from downtown Buenos Aires where
primarily upper class families own top real estate parlors located most of
the time in private country clubs." Olivier Touzeau, 5 Jun 2007
Description of the flag
The flag is 1:2 with red outer border, blue inner border, white field and
coat of arms in the middle. Olivier Touzeau, 5 Jun 2007
Meaning of the coat of arms:
The upper left quarter shows on a blue background our Lady of the
Pillar*, symbolizing the faith of the Spanish colonists.
The upper right quarter shows on a red field the historic Treaty of
The lower left quarter shows on a white field the cross built at the
entrance of the town.
The lower right quarter shows on a blue field a white dove, symbol of
The federal star is placed in the middle of the shield.
The blue waves recalls the Bourbon origin of the town.
* "Our Lady of the Pillar", a celebrated church and shrine, at
Saragossa, Spain, containing a miraculous image of the Blessed Virgin,
which is the object of very special devotion throughout the kingdom.
The image, which is placed on a marble pillar, whence the name of the
church, was crowned in 1905 with a crown designed by the Marquis of
Griñi, and valued at 450,000 pesetas (£18,750, 1910). The present
spacious church in Baroque style was begun in 1681. According to an
ancient Spanish tradition, given in the Roman Breviary (for 12
October, Ad. mat., lect. vi), the original shrine was built by St.
James the Apostle at the wish of theBlessed Virgin, who appeared to
him as he was praying by the banks of the Ebro at Saragossa."
Quote from J.M. March, Catholic Encyclopaedia (1911)