Downing Street is the street in London, England, United Kingdom, which for over two hundred years has contained the official residences of two of the most senior British cabinet ministers: the First Lord of the Treasury, an office held by the Prime Minister of the United Kingdom, and the Second Lord of the Treasury, an office held by the Chancellor of the Exchequer. The most famous address in Downing Street is 10 Downing Street, the official residence of the First Lord of the Treasury—and thus, in modern times, the residence of the Prime Minister. Number 11 is likewise a term for the Chancellor of the Exchequer or his or her office.
Downing Street is located in Whitehall in central London, a few minutes' walk from the Houses of Parliament and a little farther from Buckingham Palace. The street was built in the 1680s by Sir George Downing, 1st Baronet (1632–1689) on the site of a mansion called Hampden House. The Prime Minister, the Chancellor of the Exchequer, and the Chief Whip all have official residences in buildings along one side of the street. The houses on the other side were all replaced by the Foreign Office in the nineteenth century.