During the late 1780s, the final Spanish governor of Trinidad, José Maria Chacon, launched a crown policy of encouraging immigration by granting land and citizenship to Catholic permanent settlers. This policy resulted in a population boom from about 1,000 on the island when Chacon took office to about 18,000 when he surrendered Trinidad to the British in 1797. Road construction was among Chacon's civic improvements, including expanding the six-mile carriage path between the old capital founded inland at San Jose in 1577 and the new capital at Port of Spain. Around 1780, Chacon designated San Juan as a communications post along that road, at the site of an intersection with a cart path from the Santa Cruz Valley.
The Santa Cruz Valley was the most productive agricultural land in Trinidad. Spain originally intended to develop the plains of Trinidad as a sugar cane and rum colony. French Creole Catholic immigrants settled in the northern mountains and planted Santa Cruz and its tributary valleys almost entirely in cacao, while the hillsides above it were planted in coffee. Under a road ordinance passed in 1849, a new Royal Road (now the Eastern Main Road) bypassed San Juan, traveling a more direct route to the plantations at the head of the valley. By the 1870s, San Juan was listed as the first stop along the new railroad system. In 1884, San Juan was described as being "a miserable-looking village" on high ground north of the Royal Road and about 200 yards from the Aricagua River, still with a local road passing through. It was three miles west of San Jose, with a population of 880, five miles east of Port of Spain.
Between 1853 and 1866, Chinese and Indian farmers and laborers came to Trinidad as both sugar plantation indentured laborers and free immigrants. They often opened grocery and dry goods stores in rural areas, so the immigrant shopkeeper is a traditional stereotype in Trinidad. Their descendants include a San Juan native, Carlisle Chang (1921-2001), "the father of Trinidadian art." Chang's father had immigrated from China and his mother was ethnic Chinese born in British Guiana. When Chang was born, the city of San Juan was a small town without electricity. Chang described San Juan in his youth as a melting pot of Hindus, Muslims, Ibo, Ashanti and Yoruba, Spanish mestizo and French creoles, as well as Chinese.
By 1970, San Juan's population reached 30,000. The Croisee ("quay-zay," meaning crossroads) area around the old railway station became a market center featuring street vendors and shops, calypso music and even political rallies. The diversity of the community is readily demonstrated by San Juan Business Association 2007 president Imtiaz Ali, a children's garment manufacturer. He attended St. Mary's College, a Catholic school in Port of Spain, and is the Imam of Real Street Masjid (mosque) in San Juan.
Among the San Juan Business Association's civic proposals in 2009 is a traffic plan that will widen several streets to avoid traffic from the Santa Cruz Valley passing through the Croisee en route to Port of Spain. In 2009, the Croisee and nearby shopping areas flood with each heavy rain, but flood control had not been addressed by the Trinidad government. A marketplace to replace street vending in San Juan entered the planning stages in 2004, but had not been completed by 2009. San Juan was also asking the Ministry of Legal Affairs and the Immigration Division to open an administrative complex locally, so that San Juan residents could have easier access to birth certificate and passport offices.
