Colchester is a historic market town and the largest settlement within the borough of Colchester in the county of Essex, in south eastern England. Colchester occupies the site of what was Camulodunum, the first major Roman city in, and sometime capital of, Roman Britain. Colchester lays claim to be Britain's oldest recorded town. Colchester has been a military garrison since the Roman era and is currently home to the 16th Air Assault Brigade. In 2019 it had an estimated population of 138,131.
Situated on the River Colne, Colchester is 50 miles northeast of London and is connected to the capital by the A12 road and its railway station which is on the Great Eastern Main Line. It is seen as a popular town for commuters, and is less than 30 miles from London Stansted Airport and 20 miles from the passenger ferry port of Harwich.
Colchester is home to Colchester Castle and Colchester United Football Club. The demonym is Colcestrian.