Castle Park was opened on the 20th of October 1892 by the Lord Mayor of London.
It covers 11 hectares (although it was originally about 8 hectares in 1892). The park itself is registered Grade II on the 'English Register of Historic Parks and Gardens of Special Historic Interest in England'. The upper park and a section of the lower park are also protected as a Scheduled Ancient Monument.
Contained within the park are 4 Grade I and 4 Grade II listed buildings. The park now covers about 10% of what was the Roman town - so it was not always so green! The Castle is the largest Norman Keep ever built in Europe, (50% bigger floor area than the similar White Tower of London). It was built using the foundations of the Roman Temple of Claudius. This temple was the final refuge of the Roman citizens when Boudicca's Iceni sacked the town.
Roman Town Wall and Rampart. (Grade I Listed Building). Dated AD65/80. Located in close proximity to Duncan's Gate, and viewed as the most impressive and best preserved section of the internal rampart in Colchester. Outside of the town wall is the original town ditch.
Norman Castle Keep and Ramparts. (Grade I Listed Building and Scheduled Ancient Monument). Dated 1076 - 1100. Located near the Museum Street entrance to Upper Castle Park, and includes the foundations other bailey buildings in the ditch to the southern face of the castle. Castle built on top of foundation of Roman temple. The Castle is now home to Colchester Castle Museum.
Hollytrees Meadow. (Buried archaeology). The remains in this area of the Park appear to be mainly Roman in date and comprise a mixture of both public and domestic buildings. Previous excavations in this area have revealed a Roman Shrine, possibly the 'Mithraeum', the walls and foundations of other buildings, Roman pavements and a drain adjacent to the north south street.
Upper Castle Park - Avignon Gardens to Roman Town Wall. (Buried archaeology). Remains of the partially exposed Roman Town Houses.
Roman Town Houses - foundations and pavements. (Grade II Listed Building). Located in Upper Castle Park to the west of the Bandstand; excavated in the 1920's by Sir Mortimer Wheeler. Past excavation in the area of the town houses has revealed that there is an extensive area of remains beneath current ground level.
Middle Mill. Located at the northeast entrance into Lower Castle Park. A mill has been recorded on this site since 1101. Mill demolished by the Borough Council in 1950's.
Hollytrees House. (Grade I Listed Building). Built 1718. Garden and Castle grounds laid out by Charles Gray c.1729. Garden to south front enclosed by original eighteenth century railings (Grade II Listed).
Lucas-Lisle Memorial. First memorial in Castle Park, dedicated to two Royalist Officers shot during the siege of 1648. Constructed in 1892 on the site where the men are thought to have been executed.
Summerhouse. (Grade II Listed Building). Garden building built by Gray in 1731 as part of the original landscape design.
Rotunda. (Grade II Listed Building). Garden building built by Gray in 1747 as part of the original landscape design.
World War II defences. Anti-tank barriers located in the northeast corner of Lower Castle Park. Remains of the Eastern Command Line that was built along the River Colne.
Roman Temple Out Precinct Wall. (Grade II Listed Building). Dated c.AD54 [Temple to Emperor Claudius]. Located in Upper Park to the northwest of the castle; only partially exposed.
Entrance railings and gates. (Grade II Listed). Late nineteenth century. Cowdray Crescent, Museum street and Rye Gate entrances.
Duncan's Gate. This original Roman Gateway into the town of Colchester. It is located in the north-east corner of the park. With the exception of the Castle itself Duncan's Gate is arguably the most important single archaeological feature in Castle Park. Its location next to other contemporary Roman features such as the Roman rampart, town wall and town ditch strengthen its significance and value.
Model Boating Pond. Integral part of park layout, completed 1893.
Norman ramps and ditches. Visually dominant features of Upper Castle Park.
East Boundary Wall. (Grade II Listed). Eighteenth century. Borders Hollytrees Meadow in Upper Castle Park.