Bahía Blanca is a city in the Buenos Aires province of Argentina, situated on the Blanca Bay of the Argentine Sea. It ranks as the fourth largest city in the province and the seventeenth largest nationwide in terms of population. Serving as the seat of government for the Bahía Blanca Partido, its 2022 population was recorded at 336,574. Bahía Blanca is the central city within the Greater Bahía Blanca metropolitan area.
On March 1902, the construction of Puerto Belgrano, Argentina's largest naval base, was completed. Construction had started on 12 May 1898.
In 1912, the French Rosario and Puerto Belgrano Railway was opened in Bahía Blanca.
By 1920, there were six cinemas in Bahía Blanca due to European Immigrants bringing their customs and culture.
In January 1956, the Universidad Nacional del Sur (National University of the South) was founded.
Around 1960, the Administration of the City decided to observe a development plan, establishing criteria for further developments based on purpose.
In 1962, the FCRPB station closed and later served as the municipal library.
On 21 January 1980, the highest recorded temperature in Bahia Blanca was 43.8 °C (110.8 °F).
On 4 July 1988, the lowest recorded temperature in Bahia Blanca was −11.8 °C (10.8 °F).
Provincial Law 12101, effective since 1998, graded and listed the Estuary as The Natural Reserve of Bahía Blanca, Bahía Falsa and Bahía Verde.
In the FIBA World Championship in Indianapolis 2002, Emanuel Ginóbili, Juan Ignacio Sánchez and Alejandro Montecchia played the final match.
Since 2003, Guillermo José Garlatti is the Archbishop of Bahía Blanca.
In the Olympic Games Athens 2004, Emanuel Ginóbili, Juan Ignacio Sánchez and Alejandro Montecchia were gold medal winners.
In March 2006, a local political crisis led to the mayor requesting a leave of absence, which was granted by the city council on 27 March 2006. The mayor was indicted, and the case proceeded in the local judiciary.
On 24 August 2006, the city council decided to unseat the elected mayor for the first time in the city's history.
In 2006, Olimpo was relegated from the Argentine first division.
Up to 2006, the "Exposición Nacional de Ganadería e Industria de la Sociedad Rural de Bahía Blanca" accounted for 122 annual displays.
Prior to the snowfall in July 2009, Bahía Blanca experienced snowfall in May 2007.
In July 2009, Bahía Blanca experienced a recent significant snowfall.
In 2010, Juan Ignacio Sánchez returned home to found a professional local basketball team: Bahia Basket and Olimpo was reinstated in the Argentine first division.
In October 2022, services to Bahía Blanca were interrupted by state-owned Trenes Argentinos due to a derailment in Olavarría.
In 2022, Bahía Blanca Partido had a population of 336,574 inhabitants according to the census.
In 2022, the former FCRPB station, which had been serving as the municipal library, was destroyed by fire.
As of January 2024, Bahía Blanca had no passenger railway services.