Palace_of_Westminster The Palace of Westminster, also known as the Houses of Parliament, is a complex of buildings in London. It is the seat of the two houses of the Parliament of the United Kingdom (the House of Lords and the House of Commons). The palace lies on the north bank of the River Thames in the London borough of the City of Westminster, close to the government buildings of Whitehall.The palace contains around 1,100 rooms, 100 staircases and of corridors.