Chalfont St Peter is a large village and civil parish in southeastern Buckinghamshire, England. It is in a group of villages called The Chalfonts which also includes Chalfont St Giles and Little Chalfont. The villages lie between High Wycombe and Rickmansworth. Chalfont St Peter is one of the largest villages, with nearly 13,000 residents. The urban population for Chalfont St Peter and Gerrards Cross is 19,622, the two villages being considered a single area by the Office for National Statistics.

The Epilepsy Society is the largest medical charity in the field of epilepsy in the United Kingdom, providing services for people with epilepsy for over 100 years. Based in Chalfont St Peter, Buckinghamshire, UK, its stated mission is "to enhance the quality of life of people affected by epilepsy by promoting research, education and public awareness and by delivering specialist medical care and support services." The Epilepsy Society has close partnerships with the National Hospital for Neurology and Neurosurgery and the UCL Institute of Neurology, both located in Queen Square, London.