The 24-site US military network in Britain worth £11 billion

The US military owns 22 sites in Britain whose “replacement value” is $15.6bn (£11.4bn), according to a US War Department document found by Declassified UK.

This number of sites is larger than previously believed and more than UK governments have told parliament.

A US document published online identifies 16 of the US military’s locations in the UK and notes six “other sites” which are not specified. The document, published last year, outlines the US military’s “property portfolio” around the world as of September 2024.

Declassified has identified other locations in Britain that are likely to be hosting US military or intelligence personnel, bringing the total to at least 24.

This doesn’t cover the full scale of the US military presence in the UK, since it is believed that US military personnel are frequently, if not permanently, stationed at still more sites, such as the key Royal Navy bases at Coulport, Devonport and Faslane.

The 16 locations in Britain specified by the US War Department include the major US air bases at Lakenheath, Mildenhall, Croughton and Fairford but also lesser-known sites.

The smaller locations include a 35-acre US Air Force (USAF) site at RAF Bicester in Oxfordshire and a location said to comprise 35,397 square feet of buildings at RAF Oakhanger in Hampshire.

The document also notes US ownership of facilities at the top secret Fylingdales spy station in Yorkshire, where it possesses 5,860 square feet of building space.

Fylingdales is a joint enterprise between the US and UK and “provides a 24/7 missile warning and space surveillance capability for the UK and its allies”.

While most of the locations are operated by the USAF, the single site where the US Navy is said to be active is Lossiemouth near Inverness, the only location mentioned in Scotland.

A recent investigation by The Ferret found the US established a base there in May 2024, with the US navy helping to fund the construction of facilities for its Poseidon P8 anti-submarine spy and warplanes at the site.

The investigation also found the Scottish government was not consulted about stationing US aircraft at Lossiemouth.

Other US sites mentioned in the War Department document include a 736-acre ammunition storage location at RAF Welford in Berkshire and a “transmitter annex site” at RAF Barford St John in Oxfordshire.

These US sites stretch over 20 square miles, which is equivalent to around 11,500 football pitches, or an area larger than the city of Oxford.

Specified US military sites in Britain

Figures correct for September 2024
Source: US War Department, Assistant Secretary of War, September 2025

Successive UK governments have failed to mention in parliament some of these 16 sites as being US military operating locations, such as RAF Oakhanger and RAF Bicester. The last time Oakhanger was mentioned in parliament was in November 1996.

More recently, in answer to a parliamentary question in February 2022, the Ministry of Defence (MoD) mentioned only eight sites from where US personnel were operating, along with “undisclosed locations”.

Two years earlier, in June 2020, a minister listed 11 bases which were “designated for use by the United States Visiting Forces” in the UK. This form of words appears to keep open the possibility that US personnel are also based elsewhere.

Where are the six other sites?

The US document specifies sites in Britain that are larger than ten acres or have a replacement value of over $10m (£7.3m).

The six “other sites” identified are said to cover 7.28 acres and have a “replacement value” of £21.99m (£16m). It is not clear where these are, and the UK government imposes secrecy around the locations of US military sites and personnel in Britain.

The US list of 22 sites does not include all locations where US military or intelligence personnel are stationed, such as its embassy in London.

Another US base is RAF Wyton in Cambridgeshire, which houses Britain’s National Centre for Geospatial Intelligence and “provides intelligence support to UK Armed Forces on operations globally”.

US forces also operate in Britain as part of Nato forces in the Allied Rapid Reaction Corps (ARRC) at Imjin Barracks in Gloucestershire and at the Allied Maritime Command (MARCOM) in Northwood in London.

US military personnel are also likely to be based, either permanently or frequently, at other locations in Britain. These sites include Nato’s Joint Electronic Warfare Core Staff (JEWCS) based in Yeovilton in Somerset and the British army’s intelligence base at RAF Digby in Lincolnshire, which is home to the Joint Service Signal Unit.

US personnel may now or in the future also be stationed at Cawdor Barracks in Pembrokeshire, where the UK is developing a so-called Deep Space Advanced Radar Capability (DARC).

This is part of a network of ground-based radars in Australia, the UK and US to “provide global space monitoring, increasing AUKUS nations’ ability to detect, track and identify objects in deep space”.

Declassified also believes it likely that US military and/or civilian War Department personnel are working at the European Regional Office of the Nato Defence Innovation Accelerator for the North Atlantic (known as DIANA), which is based at Imperial College, London.

In addition to strictly military personnel, US forces also operate at intelligence sites, which are also shrouded in secrecy. As well as Fylingdales, it is known that air base Molesworth in Cambridgeshire houses both a US Defense Intelligence Agency team and the US Africa Command’s Joint Intelligence Command.

US officers also work at the Nato Intelligence Fusion Centre (NIFC) at Molesworth while two US air force intelligence squadrons are based at Mildenhall.

US intelligence personnel are also believed to be stationed at Bude, Cornwall, GCHQ’s top secret spy base which is run jointly with the US National Security Agency (NSA).

GCHQ says almost nothing about its Bude spy site but it is at the heart of a global eavesdropping network run by the NSA, which has in the past funded the upgrade of the facility.

Menwith Hill in Yorkshire, which is mentioned in the War Department document, is run by the NSA as an intelligence base, and hosts around 1,000 US personnel.

Comprising dozens of radomes, the ultra-secretive spy site is the largest intelligence-gathering, interception and surveillance base outside the US. The US document notes the War Department owns facilities at Menwith Hill covering 545 acres, with a replacement value of $850m (£622m).

The UK government reveals nothing about CIA activities or locations in Britain.

A $16bn empire

The US sites that are said to be the most expensive to replace are the sprawling air bases at Lakenheath and Mildenhall in Suffolk, valued at $5.7bn (£4.2bn) and $3bn (£2.2bn) respectively, and Fairford in Gloucestershire, valued at $1.5bn (£1.1bn).

Overall, the British facilities, valued in total at $15.6bn (£11.4bn), are the ninth most valuable in the US’s overseas military empire, the largest being Japan ($139bn) and Germany ($60bn).

The US base empire around the world has an overall “replacement value” of slightly over $500bn (£366bn), according to the US document.

Declassified asked the MoD how many US personnel were based at Oakhanger and Bicester and their roles and purpose at the sites, and why ministers have not mentioned the sites when asked in parliament about where US personnel are based in Britain.

Declassified also asked if the ministry could confirm that US military personnel are stationed at RAF Digby, RAF Wyton and the JEWCS in Yeovilton.

The ministry declined to comment and suggested Declassified file at Freedom of Information request.