St James's Square in the context of "London Library"

The Royal Institute of International Affairs, also known as Chatham House, is a British think tank based in London, England. Its stated mission is "to help governments and societies build a sustainably secure, prosperous, and just world." Conversely, it has been praised for providing a safe space for speakers and encouraging openness.

The Royal Institute of International Affairs has its headquarters in central London at 10 St James's Square, which is known as Chatham House. It is a Grade I listed 18th-century building that was designed in part by Henry Flitcroft and was occupied by three British prime ministers, including William Pitt, 1st Earl of Chatham, whose name became associated with the house. Canadian philanthropists Lieutenant-Colonel Reuben Wells Leonard and Kate Rowlands Leonard purchased the property in 1923 and then donated the building to the fledgling institute as its headquarters. As a result, the Chatham House name is used as a metonym for the institute as a whole.

The East India Club is a gentlemen's club founded in 1849 and situated at 16, St James's Square in London. The full title of the club is East India, Devonshire, Sports and Public Schools' Club due to mergers with other clubs. The club was originally founded for officers of the East India Company, and its first Patron was Prince Albert.

The Naval and Military Club, known informally as The In & Out, is a private members' club located in St James's Square, London. It was founded in 1862 for officers of the Navy and Army. It now also accepts female members, and members who have not served in the armed forces, but continues to observe service traditions.

The High Commission of Cyprus is the diplomatic mission of Cyprus in the United Kingdom. It is located at 13 St James's Square, next door to the London Library and very close to Chatham House.

In 2012 there was a small protest outside the High Commission by people claiming to have been mis-sold property on the island.

The equestrian statue of William III by John Bacon Junior stands in St James's Square in central London. It is modelled on an earlier statue of the king by John Michael Rysbrack in Queen Square, Bristol. Funding for the London statue was provided in the will of Samuel Travers, M.P., dated 1724, but nothing was done to progress the plan for a further seventy years. A design for the monument was drawn up in 1794 by Bacon's father, John Bacon Senior, but this was not executed and the commission passed to Bacon Jr., under whose direction the statue was finally erected in 1808. The statue is a Grade I listed structure.