Ashtown is a suburb of Dublin, Ireland. It is also a townland in the civil parish of Castleknock and falls largely into the postal district of Dublin 15, with some addresses in the Dublin 7 postal district.

Dublin is the capital and largest city of Ireland. On a bay at the mouth of the River Liffey, it is in the province of Leinster, bordered on the south by the Dublin Mountains, a part of the Wicklow Mountains range. At the 2022 census, the city council area had a population of 592,713, while Dublin City and its suburbs had a population of 1,263,219, and County Dublin had a population of 1,501,500.