At 387 acres (152 ha), Hadleigh Castle Country Park is one of the largest parks in Essex. The mixture of woodlands, pasture, hay meadows and marsh, punctuated with old hedgerows and ponds, provide a range of habitats for a varied and diverse wildlife. Visitors can explore the remains of Hadleigh Castle, which dates back 700 years and was immortalised in a painting by Constable.
More recently, the park was used during the London 2012 Olympics for mountain biking and has one of the best courses of its type in the UK. There is an extensive network of bike trails and paths to appeal to all levels of fitness and ability, along with designated bridleways for horse-riding, marked nature trails and a picnicking area. Events are held throughout the year.