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It was at first simply a renaming of the New Andalusia Governorate and included all of the land between 470 and 670 leagues south of the mouth of the Río Santiago along the Pacific coast. After 1617, Paraguay was separated under a separate administration (Asunción had been the capital of the governorate since Juan de Ayolas.)
Lt. GovernorFrancisco Ruíz Galán (1537–1541). Resided at Buenos Aires, prior to its abandonment.
Governor Domingo Martínez de Irala (1539–1541). Elected by the colonists, disputed the authority of Galán.
Adelantado Governor Alvar Núñez Cabeza de Vaca (1541–1544). Victorious campaign against Guarani in 1542. Arrested and returned to Spain for trial.
Governor Domingo Martínez de Irala (1544–1556). Encouraged his men to marry and keep concubines from local women. Two adelantados are unable to arrive from Spain and de Irala confirmed in his post by the king 1552. Died peacefully.
Governor Francisco Ortiz de Vergara (1558–1569). Elected by the colonists. Foundations fail at San Francisco, Sancti Spiritus, and Santa Cruz de la Sierra. Arrested and returned to Spain for trial.
Lt. Governor Alonso de Vera y Aragón (1583–1587). And de facto governor at Asunción until 1592.
Adelantado Governor Juan Torres de Vera y Aragón (1587–1592). Judge of the Royal Audience, married to Juana Ortiz de Zárate. Last appointed adelantado.
Governor Mendo de la Cueva y Benavidez (1637–1640). Defense of Buenos Aires improved. Expedition against the Calchaquís. Fort Santa Teresa erected.
Governor Ventura Mojica (or Mujica) (1640–1641).
Governor Andrés de Sandoval (1641).
Governor Jerónimo Luis de Cabrera y Garay (1641–1645). Expulsion of Portuguese attempted in governorate.
Governor Jacinto Lariz (1645–1653). Arrested.
Governor Pedro Baigorrí Ruiz (1653–1660). Three French ships successfully repelled from Buenos Aires. Calchaquís repelled from Santa Fe.
Governor Alonso Mercado y Villacorta (1660–1663). Request to be able to send two trade ships annually denied. Dutch ships permitted to dock in Buenos Aires.
Governor Juan Martínez de Salazar (1663–1674). Continued requests for free commerce. The Royal Audience of Buenos Aires briefly independent of the court at Charcas.
Governor Miguel de Salcedo y Sierraalta (1734–1742). Expulsion of foreigners from Buenos Aires ordered. Failed attempt to retake Colonia del Sacramento.
For two, somewhat different interpretations of the boundaries in unsettled areas, see Burkholder, Mark A. and Lyman L. Johnson. Colonial Latin America (10 editions). (New York: Oxford University Press, 1990), Map 2, 73 ISBN0-19-506110-1; and Lombardi, Cathryn L., John V. Lombardi and K. Lynn Stoner. Latin American History: A Teaching Atlas. (Madison: The University of Wisconsin Press, 1983), 29. ISBN0-299-09714-5