One of the fountains on Trafalgar Square. In the background the National Gallery, the National Portrait Gallery, an equestrian statue of King George IV and the Church of St. Martin in the Fields.

The national gallery by night

• Trafalgar Square is a public square in the City of Westminster, Central London, established in the early 19th century around the area formerly known as Charing Cross.

The Square's name commemorates the Battle of Trafalgar, the British naval victory in the Napoleonic Wars over France and Spain that took place on 21 October 1805 off the coast of Cape Trafalgar.

The site around Trafalgar Square had been a significant landmark since the 1200s. For centuries, distances measured from Charing Cross have served as location markers.

The site of the present square formerly contained the elaborately designed, enclosed courtyard, King's Mews. After George IV moved the mews to Buckingham Palace, the area was redeveloped by John Nash, but progress was slow after his death, and the square did not open until 1844. The 169-foot (52 m) Nelson's Column at its centre is guarded by four lion statues.

Prominent buildings facing the square include the National Gallery, St Martin-in-the-Fields, Canada House, and South Africa House.

The square has been used for community gatherings and political demonstrations, including Bloody Sunday in 1887, the culmination of the first Aldermaston March, anti-war protests, and campaigns against climate change.