Sussex, England - (1991) 3,783 km2
The area of Kingdom of Sussex is 3,783 square kilometers.
The area of East Sussex is 1,792 square kilometers.
The area of Rudgwick is 24.69 square kilometers.
The area of Chichester is 10.67 square kilometers.
The area of Icklesham is 23.5 square kilometers.
I couldn't find precise information for the area of Peasmarsh, as there are multiple places with the same name. However, Peasmarsh is a village in East Sussex, England, and typically villages in that area have a land area of a few square kilometers.
Brighton, East Sussex, England - 22 square miles
The area of Meads is 12.5 square kilometers.
The area of Vron is 20.67 square kilometers.
The area of Arcen is 11.47 square kilometers.
The area of Pals is 25.81 square kilometers.
The area of Aigne is 10.94 square kilometers.