Buenos Aires spends its first two and a half centuries as a secondary port under the distant Viceroyalty of Peru, elevated to the seat of its own viceroyalty only in 1776 as Spain reoriented toward Atlantic trade. The 25 May 1810 May Revolution deposed the Spanish viceroy in favor of a local junta, and two years into the independence war, Manuel Belgrano raised a new light-blue-and-white flag over the Rosario batteries in February 1812 — a banner that, with one addition, has flown ever since.
Formal independence was declared at the Congress of Tucumán on 9 July 1816, and José de San Martín's subsequent campaigns carried that same flag across the Andes to liberate Chile (1817–18) and on to Peru (1821). What followed at home was far rockier: decades of civil war between a Buenos Aires-centered Unitarian faction and the Federalists of the interior provinces, not settled into a stable, unified republic until national reorganization in the 1860s.
Scope of this page: the lands of present-day Argentina, c. 1516–present, six political entities. Unlike some other pages in this atlas, this one carries no internal-partition map: Argentina's 19th-century turmoil was a factional and political struggle — Unitarians versus Federalists, Buenos Aires versus the interior provinces — fought under one continuous flag rather than a genuine split into separately crowned or separately flagged entities. The provinces fought each other, but nobody raised a rival banner. Part of a larger atlas — see the linked pages at the bottom.
One border — except for the nine years Buenos Aires Province split away
Argentina's own real border, traced whole for most of its history. Buenos Aires Province seceded from the rest of the Argentine Confederation from 1852 to 1861, and the map below now draws that split as its own traced region for exactly that span, merging back into one border at the 1861 reunification. Press play, or drag the slider, to watch who held it, era to era.
Buenos Aires Province seceded from the Argentine Confederation from 1852 to 1861 — the closest this country comes to a genuine internal partition. That split was real but resolved within a single decade, inside a period this atlas’ own Argentina timeline still treats as one combined "civil war era" entry rather than two separate rival states. The map below now draws Buenos Aires Province as its own traced region for exactly that nine-year span — schematic, since no surveyed 1850s provincial boundary is being reproduced here and no specific documented flag is claimed for the seceding province — before the two regions merge back into one border at the 1861 reunification, matching this page’s own timeline.
c. 1516
Spanish colonial rule from Lima / earlier settlement
Real traced border (modern frontier); the Buenos Aires Province / rest-of-Argentina dividing line is a schematic approximation, not a surveyed 1850s provincial boundary, and appears only for the 1852–61 secession — see the rule box above.
How we know this. 6 of 6 eras on this page carry an evidence panel (3 attested, 3 not yet checked). Only the ones marked attested are confirmed by the sources named under them; where sources disagree or a claim could not be confirmed, the panel says so.
light blue – white – light blue, gold Sol de Mayo — unchanged since 1861 reunification
Migration & conquest:Immigration: mass Italian & Spanish wave (1870s–1930s)Immigration: Eastern European Jewish settlersEmigration: economic-crisis exodus (1998–2002)
Who & why: the September 1861 Battle of Pavón breaks the last major Confederation resistance, and Buenos Aires province rejoins the rest of the country under the 1853 federal constitution, finally settling the Unitarian–Federalist civil wars into one stable republic. The flag itself sees no further changes even through a genuinely turbulent 20th century — Peronism from the 1940s, a series of military coups, the brutal 1976–83 dictatorship and its "Dirty War," and the 1982 Falklands/Malvinas War against Britain.
What it represents: the same light-blue-white-light-blue horizontal triband fixed by law in 1816, shown here with the golden Sol de Mayo (Sun of May) that was added to the center stripe in 1818. The sun flag was limited to government institutions by a decree of 25 April 1884 and opened to all citizens by Law 23,208 of 1985, so the plain triband and the sun flag have both been in use; the flag replaced Buenos Aires State's own flag when the country reunified in 1861.
Attestedhow we know this
Wikipedia says the flag was officially recognised on 20 July 1816 at Tucumán, that Pueyrredón established the sun flag on 25 January 1818, that on unification in 1861 the national flag replaced Buenos Aires State's flag, that Roca's decree of 25 April 1884 limited the sun flag to government institutions, that decrees of 1943 and Decree 10,302/1944 regulated it, that Law 23,208 of 1985 let individuals use it, and that Decree 1650/2010 standardised colours and proportions. FOTW (Gregoric) says Congress at Tucumán passed the plain triband in 1816, that the Congress, then in Buenos Aires, created the war flag by adding the sun on 25 February 1818, and that the 1884 decree defined the 1:2 ratio and restricted the sun flag to military and government agencies.
Argentina — Flags of the World (CRW Flags) compiled
Not established: The sources differ on the sun flag's date (25 January or 25 February 1818). FOTW gives only the year for Tucumán, and does not cover 1861. This page used to say the sun flag became the sole civil and state flag.
Paint guide
Proportions9:14, three equal horizontal bands.
LayoutLight blue – white – light blue horizontal triband, gold sun with a simple face centered on the white stripe.
Light blue (celeste)#74ACDF
White#F4EFE1
Sol de Mayo, gold#F6B40E
the same law-fixed flag, flown by both sides of a fractured country
1820s – 1861
Civil war era / Argentine Confederation
Confederation, civil conflictJuan Manuel de RosasRoman Catholic (traditional)
Who & why: after 1820 the fragile national government collapses, and the country splinters into loosely confederated provinces racked by recurring war between Unitarians, who wanted a centralized state run from Buenos Aires, and Federalists, who wanted provincial autonomy. Juan Manuel de Rosas, governor of Buenos Aires province, dominates the era's federalist coalition from 1829 to 1852, controlling the confederation's foreign affairs without ever fully unifying it under a written constitution. His fall at Caseros in 1852 opens a decade of further struggle between Buenos Aires and the rest of the Confederation before Pavón finally resolves it in 1861.
What it represents: Wikipedia contradicts the idea of one shared banner: Rosas made the official shade turquoise blue in 1829, unofficial Rosas-era variants had four Phrygian caps and a red sun, Federalist units used dark blue and red-and-white flags, and the State of Buenos Aires flew its own flag from 1852 to 1861. Flags of the World does not cover this period.
Not yet checked against sourceshow we know this
Wikipedia (Flag of Argentina): Rosas made the official shade turquoise blue in 1829, unofficial Rosas-era variants had four Phrygian caps and a red sun, Federalist units used dark blue and red-and-white flags, and the State of Buenos Aires flew its own flag from 1852 to 1861. Wikipedia (Argentine Confederation): infobox flag captioned 1836-1852, State of Buenos Aires secession 11 September 1852, no flag descriptions. FOTW's historical page lists Quiroga flags of 1826-1833 and links to external Olle pages for 1829-1862, but does not describe a Confederation state flag.
Not established: The Wikipedia flag article contradicts the page's 'one law-fixed flag flown by both sides'; the second publisher does not describe Confederation or Buenos Aires state flags.
Paint guide
ProportionsNo single ratio enforced during this period; shown at 3:2.
LayoutLight blue – white – light blue horizontal triband, gold sun centered on the white stripe.
Light blue (celeste)#74ACDF
White#F4EFE1
Sol de Mayo, gold#F6B40E
the sun is added to the stripe in 1818, two years into this era
1816 – 1820s
United Provinces of the Río de la Plata (independence declared)
Republic, independence declaredJuan Martín de PueyrredónRoman Catholic (established, per 1819 constitution)
Who & why: delegates at the Congress of Tucumán, with San Martín's army already in the field, formally declare independence from Spain on 9 July 1816. The following year San Martín leads his army across the Andes, liberating Chile by 1818, and in 1821 pushes on to liberate Peru — extending the reach of the new flag far beyond the provinces that raised it.
What it represents: Belgrano's light-blue-and-white banner, already the flag of the independence war, is joined on 25 February 1818 by the gold Sol de Mayo on its center stripe, commemorating the May Revolution; the design from this point on is essentially the flag Argentina still flies.
Attestedhow we know this
Wikipedia says independence was declared on 9 July 1816 and the flag officially recognised on 20 July 1816, and that Pueyrredón established the flag with the Sun of May on 25 January 1818 (a 1944 decree says 25 February). FOTW (Gregoric) says the Tucumán Congress passed the plain triband in 1816 and that the Congress in Buenos Aires added the sun on 25 February 1818.
Who & why: the 25 May 1810 May Revolution in Buenos Aires deposes the Spanish viceroy, replacing him with a local junta that governs, at first, nominally in the name of the deposed Spanish king Ferdinand VII while war with royalist forces spreads across the interior. Manuel Belgrano, commanding troops at the Rosario batteries on the Paraná River, raises a new light-blue-and-white flag on 27 February 1812 — a banner meant for the independence war effort rather than any single province.
What it represents: two horizontal light-blue stripes flanking a white one, with no sun or other device yet; the colors are traditionally linked to the sky over Buenos Aires on the day of the revolution, though the exact reasoning is debated. It is adopted informally as the flag of the patriot army well before any government formally sanctions it.
Attestedhow we know this
Wikipedia says Belgrano wrote on 26 February 1812 proposing a national flag, that it was first raised at Rosario on 27 February 1812, that the First Triumvirate ordered him in early March 1812 to stop using it, that he had it blessed at Jujuy on 25 May 1812 and called it the national flag, and that the origin of the colours cannot be accurately established. FOTW (Gregoric) says there are several theories about the design raised on 27 February 1812 and that triband flags were in use by 1814 without the sun.
Argentina — Flags of the World (CRW Flags) compiled
Not established: This page's «adopted informally as the flag of the patriot army» is close to Wikipedia's account, which also says the government told him to stop.
Paint guide
ProportionsNo fixed ratio recorded; shown at 3:2.
LayoutLight blue – white – light blue horizontal triband, no device.
Light blue (celeste)#74ACDF
White#F4EFE1
Cross of Burgundy on white — the Spanish crown's military and naval ensign
1776 – 1810
Viceroyalty of the Río de la Plata (Spanish colonial)
ColonyPedro de CevallosRoman Catholic (Spanish Empire)
Migration & conquest:Immigration: forced deportation via the slave trade
Ruling house:House of Bourbon (Spain)
Who & why: Spain elevates Buenos Aires to the seat of a brand-new viceroyalty in 1776, carving it out of the older Viceroyalty of Peru. The move reflects the growing weight of Atlantic trade — silver, hides, and contraband moving through the Río de la Plata estuary — over the older, more cumbersome Pacific route through Lima and Panama. Buenos Aires grows quickly into the region's real administrative and commercial center, setting up the conditions for the 1810 revolution three and a half decades later.
What it represents: Wikipedia says the first flags in the territory were Spanish crown flags and that the last formal Spanish flag, set by Charles III in 1785, was red and yellow. Wikipedia and Flags of the World say the Cross of Burgundy remained in use in Spain's overseas possessions and as a jack until 1785, and FOTW that it stayed the Spanish military flag on land to 1843; neither mentions the Río de la Plata, so it is shown here as representative of royal authority, not as a documented local flag.
Not yet checked against sourceshow we know this
Wikipedia (Flag of Argentina): the last formal Spanish flag, set by Charles III in 1785, was red and yellow. Wikipedia (Cross of Burgundy Flag): the Burgundy flag remained in use in Spain's overseas empire (Bandera de Ultramar) and was reportedly a jack until Charles III's red-yellow-red naval ensign of 1785. FOTW: the Burgundy saltire was an ensign 1506-1670s and a jack until 1785, and remained the Spanish military flag on land up to 1843.
Not established: Neither publisher mentions the Rio de la Plata, so use of the Burgundy cross there is inferred; as a naval ensign it was superseded by the red-yellow flag in 1785, so the 'military and naval ensign' caption fits only 1776-1785 for ships.
Paint guide
ProportionsNo fixed civil ratio; shown at 3:2.
LayoutWhite field, red saltire (Cross of Burgundy) — shown simplified as straight diagonal bars rather than the traditional jagged, knotted-branch outline.
White#F4EFE1
Cross, red#9C3B28
the same Spanish ensign, administered from distant Lima
c. 1516 – 1776
Spanish colonial rule from Lima / earlier settlement
ColonyNo single ruler documentedRoman Catholic (Spanish Empire)
Ruling house:House of Habsburg (Spain)House of Bourbon (Spain)
Who & why: before Spanish contact, the region is home to peoples including the Diaguita in the northwest, the Guaraní along the upper Paraná and Uruguay rivers, and the Mapuche in the south — none of them under any single flag or crown. Spanish exploration reaches the Río de la Plata estuary in 1516 with Juan Díaz de Solís; early Spanish settlement is sparse and slow, with Buenos Aires itself founded and then abandoned in 1536 before a lasting refoundation in 1580. For most of this span the territory is administered, thinly and from very far away, as a minor holding of the Viceroyalty of Peru, seated in Lima.
What it represents: no separate flag exists for this remote and lightly settled corner of the Spanish empire; a Spanish crown flag stands in here (the Cross of Burgundy drawn on this page is not confirmed by the sources read), honestly, for the crown's nominal authority rather than for any flag specific to the future Argentina.
Not yet checked against sourceshow we know this
Wikipedia (Cross of Burgundy Flag): earliest use in Spain 1506 and later overseas as the Bandera de Ultramar. FOTW (Spain 1506-1700): the main Spanish symbol from Charles I (1518) to Charles II (1665) was the red Burgundy cross on varying fields, 'a military banner' possibly carried by the conquistadors, with separate ensigns for American waters and for expeditions to the Indies.
Not established: Neither publisher mentions Peru or the Rio de la Plata, and the Burgundy cross is described as a military banner with varying field colours, not an administrative flag; no flag specific to the territory is documented.
Paint guide
ProportionsNo fixed civil ratio; shown at 3:2.
LayoutWhite field, red saltire (Cross of Burgundy), simplified.
White#F4EFE1
Cross, red#9C3B28
Reading the tags
Colony — under Spanish viceregal authority
Revolutionary junta — governing in revolt, independence not yet declared
Republic, independence declared — sovereign, formally declared at Tucumán
Confederation, civil conflict — loosely joined provinces at war with each other
Republic — unified, stable federal republic
Leader — the named ruler most associated with the era's start
State religion — the official/established faith, not the population's
Find the records
Family history research for Argentina lives in a different project, Record Atlas, which maps which archive actually holds the paper for a given place and era.