Colchester in Essex is Britain’s oldest recorded town so hosts many historical landmarks such as Colchester Castle.OS Landranger map 168 also features the nearby town of Maldon by the River Blackwater estuary, which is home to local saltwater marshes rich in wildlife. With this map you will receive a code for use on your i OS or Android smartphone or tablet. Find our more at Mobile Download FAQ. The OS Landranger map for Colchester is available in both the standard paper version & weatherproof " Active" version.