With most of lands from the low Llobregat valley, the current town of Sant Joan Despí has been inhabited for a very long time (Sant Joan Despí, artistic and cultural heritage, CEDIP, 1999).
During the Roman Empire period, some villas and country houses for agriculture were built here. This area was known as Vico Miziano back then.
During the Middle Ages, after the sarrain invasion, which destroyed and depopulated the area, since the 10th century a strong process of repopulation started. The foundation of the Saint John Baptist church is an example of this initiative, which is documented since the beginning of the 11th century.
During the 15th, 16th and 17th century, the region went through several war episodes and outbreaks of plague which devastated Catalonia and made the population go down dramatically. Back then, the economy was mostly agricultural, with some fishing in the river Llobregat.
Until the mid 18th century, the royal pathway whitch used to link Madrid and Barcelona went through the town and was an important development engine. With the construction of a new route during the reign of King Charles III (currently N-11), Sant Joan Despí stopped being a town to pass through and from that moment on started being relatively isolated, which has influenced its historical evolution. According to data from the traveller Francisco de Zamora, back then, the town almost had only one street.
Until 1830, the town of Sant Joan Despí used to spread on both sides of what now is known as Bon Viatge and went on through carrer del Mig and carrer de Catalunya to arrive to Despoblat and the Raval de les Begudes, where there were some fields and country houses.
In the late 19th century, the “eixample de Sant Joan Despí” was born, between the streets de les Torres and Francesc Macià. It was a straight line, parallel to the railway where there were several holiday houses which belonged to people from Barcelona during the late 19th and the early 20th century. If we stand on the dividing line the railway represents for Sant Joan Despí and we look at the upper area, in a mid point we would find the Avinguda Barcelona (previously known as riera de la Fontsanta) and we could see Samontà on the left and Les Planes on the right. Samontà was the most inclined part and spread until Sant Just Desvern and Esplugues de Llobregat. In contrast, on the right, on a flat area, Les Planes had its borders with Cornellà de Llobregat.
We can see how the old town of Sant Joan Despí looked in the 20th century in the book “Sant Joan Despí, un recorregut per la història”, by Alvar Maduell from the volume Province of Barcelona of the General Geography of Catalonia. “Town which, with the caseriu de les begudes and 32 houses, has 281 buildings. It's located on the left side of the river Llobregat. The railway from Tarragona to Barcelona goes through the town and has a stop there; the Canal of the Infanta Carlota and the pathway from Cornellà to Sant Feliu also go through Sant Joan Despí. It belongs to the Bishopric of Barcelona. It has a church in honor of Saint John, run by a prior; a municipal study, a public library and a savings bank; two choirs, one recreative and the other political; a sub-delegation shall of the Institut Agrícola Català de Sant Isidre and the Cambra Agrícola del Baix Llobregat. Its local festival takes place the 23rd of August. Its industrial activity consists in a cardboard factory and an oven. Its area is flat and its weather is temperate and healthy; wheat, corn, legumes, hemp and wine is its main agriculture.”
In Samontà, a new residential area was planned in 1926 by the architect Josep M. Jujol. This project meant the building of a new neighborhood, perfectly outlined and planned, with a square from where all the new streets spread out forming a new whole neighborhood. This project remained in stand by for a few years and was resumed around 1947. However, the project did not succeed and the regional plan from 1953 made this area be considered an industrial area (years later, it became the Fontsanta Industrial State) and Gallina Blanca was the first company to arrive, being followed by many others.
That made the idea of making the center of Sant Joan Despí spread beyond the railway disappear. Furthermore, a new barrier to split the old center and the rest (La Mossota, Pla del Vent) appeared. Later, a new neighborhood was born: Les Planes, which started receiving all the workers who had left their villages (mostly from Andalusia) to work in new industrial state.
During the 60's and 70's, Sant Joan Despí was growing unstoppably. In 1960, the town had 4.711 people, and 16.055 by 1970. Les Planes was completely built and in the old center several buildings were demolished to build new blocks of flats. Most of them didn't meet the reasonable quality standards.
During the 80's, the public administrations being democratized, towns regulation was one of the main projects for the governments. Due to the economical crisis, that was done little by little: green areas, parks, equipments...
In the mid 80's, Sant Joan Despí experienced a new urban growth: the residential area of Sant Joan and Torreblanca were born. In 1985, the Corporació Catalana de Ràdio i Televisió decided to place the TV3 facilities on the area of Sant Joan -that's why that neighborhood is also known as TV3-. Many construction companies came after and started building blocks of flats until 1997. This neighborhood was integrated with the rest after that, mainly with Les Planes, after building the Marquès de Monistrol bridge and the Fontsanta park.
The beginning of a new century is also the beginning of the eixample sud-oest, a totally new area that goes from the Carrer Major to the river.
Sant Joan Despí is nowadays a town which has reached a population of 32.000 people. A town with four neighborhoods, well defined and equipped. It has a good bunch of green areas, a library, two sports centers and many other sports areas, civic centers... A town with quality of life.