Trafalgar Square is a square in London, that commemorates the Battle of Trafalgar (1805), a British naval victory of the Napoleonic Wars.

The square consists of a large central area surrounded by roadways on three sides, and stairs leading to the National Gallery on the other. The roads which cross the square form part of the busy A4 road, and prior to 2003, the square was surrounded by a one-way traffic system on all sides. Underpasses attached to Charing Cross tube station allow pedestrians to avoid traffic.

On the north side of the square is the National Gallery and to its east the St Martin's-in-the-Fields church. The square adjoins The Mall via Admiralty Arch to the southwest. To the south is Whitehall, to the east Strand and South Africa House, to the north Charing Cross Road and on the west side is Canada House.

The nearest underground station to Trafalgar Square are Charing Cross (Northern, Bakerloo lines) which has an exit in the square. Embankment (District, Circle lines) and Leicester Square (Northern, Piccadilly lines).