The parliament of which European country has been housed in Leinster House since 1922?

Leinster House (Irish: 'Teach Laighean') is the seat of the Oireachtas, the parliament of Ireland.

Leinster House was originally the ducal palace of the Dukes of Leinster. Since 1922, it is a complex of buildings, of which the former ducal palace is the core, which house Oireachtas Éireann, its members and staff. The most recognisable part of the complex, and the "public face" of Leinster House, continues to be the former ducal palace at the core of the complex.

Leinster House was the former ducal residence in Dublin of the Duke of Leinster, and since 1922 served as the parliament building of the Irish Free State, the predecessor of the modern Irish state, before which it functioned as the headquarters of the Royal Dublin Society. The society's famous Dublin Spring Show and Dublin Horse Show were held on its Leinster Lawn, facing Merrion Square.