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.

The Chatham House Rule evolved to facilitate frank and honest discussion on controversial or unpopular issues by speakers who may not have otherwise had the appropriate forum to speak freely.

[4] Chatham House research is structured around five thematic programmes, comprising: environment and society; global economy and finance; global health security; international law; and international security; as well as seven regional programmes, covering Africa, the Asia-Pacific region, Europe, the Middle East and North Africa, Russia and Eurasia, the USA and Americas and the UK in the World launched in 2023.

[9] The Royal Institute of International Affairs originated in a meeting, convened by Lionel Curtis, of the American and British delegates to the Paris Peace Conference on 30 May 1919.

[14] The survey continued until 1963 and was well received throughout the Institution, coming to be known as 'the characteristic external expression of Chatham House research: a pioneer in method and a model for scholarship.

Ivison Macadam was appointed to the position (Secretary and then Director-General),[19] in which he oversaw the institute's rapid expansion with its growing research, organisational and financial needs,[20] a role he occupied until 1955.

Macadam was able to secure funding to expand the physical plant of the Institute by acquiring the freeholds of 6 Duke of York Street, then called York Street (largely through the generosity of Waldorf Astor, John Power, and others) and later 9 St James's Square, then the Portland Club, in 1943 (through a donation to cover its purchase by Henry Price), and connect these adjoining properties to the original freehold property of Chatham House at 10 St James Square (with the cost of these connections covered by Astor's sons, William, David, and John).

The group, which included leading economists such as John Maynard Keynes, conducted a three-year study into the developing economic issues which the post-war international monetary settlement created.

[27] At the outbreak of the Second World War the institute was decentralised for security reasons, with many of the staff moving to Balliol College, Oxford from Chatham House's main buildings in St James's Square.

There were four deputy directors, Alfred Zimmern, George N. Clark, Herbert J. Patton and Charles K. Webster, and a number of experts in nineteen national divisions.

The Institute reopened formally on 28 October 1943; the session was addressed by the American commanding general of U.S. Army logistics forces in the ETO, then-Maj. Gen. John C. H. Lee, who spent a substantial part of his time working with the Theater G-5 officer (Civil-Military Affairs), MG Ray W. Barker.

Combining this with the institute's early support of the League of Nations and impact of the gold study on the Bretton Woods system, Chatham House found itself to be a leading actor in international political and economic redevelopment.

[28] In reaction to the changing post-war world, Chatham House embarked on a number of studies relating to Britain and the Commonwealth's new political stature, in light of growing calls for decolonisation and the development of the Cold War.

For example, Chatham House's Far East programme, created with the intention of improving Anglo-Japanese relations in the long and short term, was bolstered by the support of the Japan 2000 group in 1984.

Chatham House said the Angola Forum was intended to create an international platform for "forward looking, policy focused and influential debate and research".

[39] The Chatham House Prize was launched in 2005, recognising heads of state and organisations that made a significant contribution to international relations during the previous year.

[44] Christopher Sabatini, a senior fellow at Chatham House, leads a project promoting opposition to the Venezuelan government of Nicholas Maduro.

[45] In 2015, several reports were published by Chatham House, including Nigeria's Booming Borders: The Drivers and Consequences of Unrecorded Trade, which urges formalising trade and driving more sustainable and less volatile growth;[46] Changing Climate, Changing Diets: Pathways to Lower Meat Consumption examines a reduction in global meat consumption as critical to keeping global warming below the "danger level" of two degrees Celsius;[47] Heat, Light and Power for Refugees: Saving Lives, Reducing Costs examines the reasons why energy provision to displaced people undermines the fundamental humanitarian aims of assistance;[48] and Towards a New Global Business Model for Antibiotics: Delinking Revenues from Sales argued for revenues for pharmaceutical companies to be de-linked from sales of antibiotics to avoid their over-use and avert a public health crisis.

[50] 2017 reports included The Struggle for Ukraine, an exploration of, four years after its Euromaidan revolution, Ukraine's fight for survival as an independent and viable state;[51] Chokepoints and Vulnerabilities in Global Food Trade advocates for policymakers to take immediate action to mitigate the risk of severe disruption at certain ports, maritime straits, and inland transport routes, which could have devastating knock-on effects for global food security;[52] Collective Action on Corruption in Nigeria: A Social Norms Approach to Connecting Society and Institutions examines how anti-corruption efforts could be made significantly more effective through new ways of understanding why people engage in the practice;[53] and America's International Role Under Donald Trump explores the impact of US President Donald Trump's personality and style—brash, unpredictable, contradictory and thin-skinned—on his engagement in foreign affairs.

[60] In 2020 and 2021, there were reports on The Business Case for Investment in Nutrition claiming to be the first of its kind to reveal the hidden costs of malnutrition for business, and the extent to which these costs are recognised and addressed by multinational companies[61] and Myths and misconceptions in the debate on Russia which aims to deconstruct sixteen of the most prevalent myths and misconceptions that shape contemporary Western thinking on Russia.

Chatham House has three presidents: Lord Darling of Roulanish, former Chancellor of the Exchequer, Baroness Manningham-Buller, a crossbench peer and former Director General of MI5, and Helen Clark, former prime minister of New Zealand.

[70] In November 2016, Chatham House was named Prospect magazine's Think-Tank of the Year, as well as the winner in the UK categories for International Affairs and Energy and Environment.