Why did many Georgian houses in Dublin become slums during the 19th century?

The decline of Dublin’s elegant Georgian houses into slums during the 19th century was primarily triggered by the Act of Union in 1801. This legislation abolished the Irish Parliament, which led to a significant reduction in the city's status and prompted the leading figures of the Ascendancy to return to England, as they no longer had governmental duties requiring their presence in Dublin.1

As these wealthy residents departed, the once-elegant Georgian structures were rented out piecemeal to the growing population. The situation worsened significantly following the Irish Potato Famine (1845–49), which caused tens of thousands of dispossessed peasants to flock into the city from the countryside, leading to extreme overcrowding. By the early 20th century, the conditions had become dire, with investigations revealing that 20,000 families were each living in a single room, and the city suffered from a lack of basic sanitation and high mortality rates.1