The Mardyke is an area in Cork city, on the northern half of the long western part of the island formed by the two channels of the River Lee near the city centre. It was historically left as open space, because the land along the north channel of the river is prone to flooding. From east to west these open spaces are: Presentation Brothers College, a boy's secondary school; the Mardyke ground of Cork County Cricket Club; Fitzgerald Park, which includes Cork Public Museum; Sunday's Well Lawn Tennis Club; and the athletic grounds of University College Cork.

The original dyke was constructed in 1719 by Edward Webber, the city clerk, who owned what were then marshy islands west of the walled city. He drained and landscaped the area, building a dyke topped by a straight promenade leading to a redbrick teahouse in Dutch style. The area became fashionable and the promenade was dubbed the Red House Walk or Meer Dyke Walk after the Meer Dyke in Amsterdam. Dutch influence was strong among the Protestant Ascendancy in the decades after the Williamite War in Ireland. After Webber's death the land was bought and further developed by future mayor James Morrison. The route of the promenade corresponds to the modern streets Dyke Parade and Mardyke Walk.

The Mardyke is mentioned in James Joyce's A Portrait of the Artist as a Young Man: "The leaves of the trees along the Mardyke were astir and whispering in the sunlight. A team of cricketers passed, agile young men in flannels and blazers, one of them carrying the long green wicket bag."

In the early 20th century, the then Lord Mayor of Cork Edward Fitzgerald, proposed that a large public exhibition be held in Cork in the Mardyke area. 44 acres of Mardyke parkland were hence set aside as the site of the 1902 Cork International Exhibition. The central section of the Mardyke exhibition site (approximately 12 acres) is now known as Fitzgerald's Park, and includes the Cork Public Museum and a large children's play area. The area of the park is joined to Sunday's Well across the River Lee by Daly's bridge (a pedestrian suspension bridge known locally as the "Shakey Bridge").