Limerick City is almost 1,100 years old. It has been a Viking settlement, a medieval walled town, a Georgian city and is now a modern, vibrant metropolitan area with a rich and historic hinterland. The longest river in Ireland flows through the city.

The River Shannon began flowing along its present course after the end of the last glacial period. According to Irish mythology, the river was named after a woman named Sionann (older spelling: Sínann or Sínand), the granddaughter of Lir. She went to Connla's Well to find wisdom, despite being warned not to approach it. In some sources she, like Fionn mac Cumhaill, caught and ate the Salmon of Wisdom who swam there, becoming the wisest being on Earth. However, the well then burst forth, drowning Sionann and carrying her out to sea. It is believed that Sionann was the goddess of the river. Patricia Monaghan notes that: "The drowning of a goddess in a river is common in Irish mythology and typically represents the dissolving of her divine power into the water, which then gives life to the land".

The River Shannon reputedly hosts a river monster named Cata, first appearing in the medieval Book of Lismore. In this manuscript we are told that Senán, patron saint of County Clare, defeated the monster at Inis Cathaigh. Cata is described as a large monster with a horse's mane, gleaming eyes, thick feet, nails of iron and a whale's tail. Vikings settled in the region in the 10th century and used the river to raid the rich monasteries deep inland. 

In the 17th century, the River Shannon was of major strategic importance in military campaigns in Ireland, as it formed a physical boundary between the east and west of the country. In the Irish Confederate Wars of 1641–53, the Irish retreated behind the Shannon in 1650 and held out for two further years against English Parliamentarian forces. In preparing a land settlement, or plantation after his conquest of Ireland Oliver Cromwell reputedly said the remaining Irish landowners would go to "Hell or Connacht", referring to their choice of forced migration west across the River Shannon, or death, thus freeing up the eastern landholdings for the incoming English settlers. In the Williamite War in Ireland (1689–91), the Jacobites also retreated behind the Shannon after their defeat at the Battle of the Boyne in 1690. Athlone and Limerick, cities commanding bridges over the river, saw bloody sieges. 

As late as 1916, the leaders of the Easter Rising planned to have their forces in the west "hold the line of the Shannon". However, in the event, the rebels were neither well enough armed nor equipped to attempt such an ambitious policy. The River Shannon is closely bound up with Ireland's social, cultural, military, economic and political history. In the 1920s, the Irish government undertook the largest engineering project in the world, building the Ardnacrusha Hydroelectric Station to power the nation, and exists until today. The process was documented by local artist Seán Keating.

Today the River Shannon continues to inspire the citizens of Limerick City including its artists; one of the best known examples in the world is Bill Whelan’s Riverdance. Limerick City is also home to Riverfest (Winner of Best Event 2019 at the Event Industry Awards), the Museum of Mythological Water Beasts at Ormston House, SwimAble Limerick and much more.