The River Tolka (Irish: An Tulcha, "the flood") is one of the three main rivers of Dublin, Ireland, alongside the Liffey and the Dodder. It originates east of Dunshaughlin in County Meath, about 25 kilometers northwest of Dublin, and flows southeast through rural areas before entering County Fingal near Clonee and eventually reaching Dublin’s northern suburbs. With an average water flow, the Tolka is Dublin’s second-largest river after the Liffey, though it moves more slowly than the Dodder.
The river passes through several neighborhoods, including Blanchardstown, Finglas, Glasnevin, and Drumcondra, before emptying into Dublin Bay between East Wall and Clontarf. Along its course, it collects numerous tributaries, such as the Castle Stream near Dunboyne and the Finglas River. The Tolka runs through various parks, like Tolka Valley Park and alongside the National Botanic Gardens, providing habitat for wildlife including otters, salmon, and kingfishers, though it often faces pollution challenges in urban sections.
Historically, the Tolka is known for occasional flooding, such as in December 1954 or November 2002, which significantly impacted parts of Dublin. Despite its importance, it remains less famous than the Liffey but has a lasting influence on the landscape and history of North Dublin.