South Essex Partnership NHS Foundation Trust is one of the largest NHS providers in the country of health and social care services for people with mental health problems and people with learning disabilities. The Trust covers a population of almost 709,000 in South Essex, and has an annual income of £78.3 million to deliver services for local people.

The area covered is to the east of central London, on the northern bank of the Thames estuary and forms part of the area overseen by the new Essex Strategic Health Authority.

The areas they serve in South Essex include Castle Point, Rochford & Rayleigh, Southend, Basildon, Billericay, Wickford & Brentwood and Thurrock. They also deliver forensic mental health services for the whole of Essex.

South Essex Partnership NHS Trust deliver services from around 100 premises across south Essex. For mental health services, their main sites include Runwell Hospital, Rochford Hospital, Basildon Mental Health Unit and Thurrock Community Hospital. Learning disability services are delivered in a range of community-based accommodation throughout south Essex.