St. Giles, like Alsatia, was a notorious thieves' rookery where watchmen and constables rarely ventured. It was also one of the poorest areas of London. Nell Gwyn was born in St. Giles and her first job (at the age of seven), was pouring drinks in a bawdy house in Lewkenor's Lane.

Houses in St. Giles were often nothing more than windowless huts with dirt floors. It was not uncommon for several people to share one room, perhaps with an assortment of pigs and chickens as well.

There was no drainage in St. Giles; streets were cleaned only by the rain. Huge piles of rubbish were swept together into rotting "laystalls" outside people's houses.

The Plague swept through St. Giles, aided by the insanitary conditions prevalent throughout the area. Huge burial pits were dug in the yard of St. Giles's Church, the bodies piled in indiscriminate masses.

The clearing of the city after the Great Fire added to the overcrowding of St. Giles, making it a worse slum than ever.