Brownsea Island (also known as Branksea) lies in Poole Harbour in Dorset. It is the largest of eight islands in the harbour and can be reached by public ferry or private boat. There is a wharf and a small dock near the main castle. The island is 1.5 miles (2.4 km) long by 0.75 mile (1.2 km) wide and consists of 500 acres of woodland (mostly consisting of Pine, Oak and Silver Birch), heathland and salt-marsh.
The island is famous for its formation of the Scout movement, following an experimental camp there in 1907. Except for the church and a few other buildings which are leased or managed by third parties, the island is owned by the National Trust. The island supports a wide variety of wildlife, including the Red Squirrel and the northern portion of the island is a Nature Reserve managed by Dorset Wildlife Trust and an important habitat for birds.