Royal Air Force Culmhead or more simply RAF Culmhead is a former Royal Air Force station, situated at Churchstanton on the Blackdown Hills in Somerset, England.

There is now an industrial estate – derived from the later Composite Signals Organisation Station (CSOS) – right in the middle of the place where the three runways meet.

[2] RAF Culmhead was a typical three-runway fighter airfield, with blast pens built around the site along with ten blister hangars.

[2] The site was also used for the testing of barrage balloon wire cutters in 1942 by 02 Detachment of the Royal Aircraft Establishment from Farnborough.

[2] After D-Day in 1944, the airfield was used for training on Gloster Meteors, the first jet engined aircraft in RAF service.

[4] In the autumn of 1944 the surviving squadrons were transferred to other sites and the station wound down, becoming a glider training school and maintenance unit until RAF Culmhead closed in August 1946.

[4] The following units were also here at some point:[6] From the 1950s, the site was partially reused as Composite Signals Organisation Station (CSOS) Culmhead, performing signals research functions, operated under the aegis of Government Communications Headquarters (GCHQ), with a cluster of buildings covering some 4.4 hectares being constructed approximately in the centre of the former airfield.