The celebrated Trafalgar Square consists of King's Mews since the time of Edward I on the north side and the original Charing Cross on the south side. The Charing Cross is where the Strand from the city met Whitehall coming north from the Westminster. The Charing Cross is considered the heart of London being the midpoint of the twin cities. Landscape architect John Nash redeveloped the area in the 1820s through the directives of the Prince Regent. Nash cleared the square as part of his Charing Cross Improvement Scheme. It was in 1845 that the present architecture of the square was completed. And it was primarily due to Sir Charles Barry. Consists of a large central area surrounded by roadways on three sides and stairs leading to the National Gallery on the other, the square was surrounded by a one-way traffic system prior to 2003. Thus underpasses were constructed attached to Charing Cross tube station to allow pedestrians to pass to avoid traffic. Recent works have reduced the width of the roads and closed the northern side of the square to traffic.

Meanwhile in the center of the square sits the so-called Nelson’s Column. The column is surrounded by water fountains designed by Sir Edwin Lutyens in 1939 and four large bronze lions sculpted by Sir Edward Landseer. The column is topped by a statue of Horatio, Viscount Nelson, the admiral who commanded the British Fleet at Trafalgar. The bronze lions is said to have used the metal from the cannon of the French fleet. The fountains in the center of the square are constructed in memory of Lord Jellicoe (western side) and Lord Beatty (eastern side), Jellicoe being the Senior Officer.

The National Gallery can be seen on the north side of the square while the St. Martin-in-the-Fields Church can be seen in the east of the square. 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 the Canada House. The statues of James II and George Washington are on the lawn in front of the National Gallery. James II is located to the west of the entrance portico and George Washington to the east. The latter statue was a gift from the state of Virginia. It stands on soil imported from the United States in order to honor Washington's declaration that he would never set foot on British soil again.

The Trafalgar Square has established itself as a social and political location for visitors and Londoners alike. It developed over the course of its history from a walkway peopled with figures of national heroes, into the country’s foremost political place. It was historian Rodney Mace who coined the Trafalgar Square as such. The symbolic importance of the square was demonstrated in 1940 when the Nazi SS developed secret plans to transfer Nelson's Column to Berlin following an expected German invasion, as related by Norman Longmate in If Britain Had Fallen (1972).