--- - |2 Abstract Throughout history, the planning and construction of a dam has become symbolic of wider political events and processes. This paper investigates how the Tryweryn scheme in north‐west Wales in the 1950s and 1960s became a central signifier within the emergent Welsh nationalism of the period. The project, providing water to the city of Liverpool, flooded the village of Capel Celyn and displaced its 48 residents. However, the opposition to the project extended beyond this rural community, with the scheme becoming a focal point for Welsh nationalism. This paper explores this significance, arguing that the Tryweryn scheme was articulated in a number of ways that elevated the project from a local issue to a national outcry, resulting in the term ‘Tryweryn’ having a resonance that continues to this day. - 'Journal of Historical Sociology, EarlyView. '