1918–1950 • The Borough of Colchester; and • The
Rural District of Lexden and Winstree except the detached part of the parish of
Inworth which was wholly surrounded by the parishes of
Great Braxted and Kelvedon.
The area comprising the Rural District of Lexden and Winstree had largely been part of the Harwich Division. 1950–1983 • The Borough of Colchester; • The Urban District of West Mersea; and • The Rural District of Lexden and Winstree.
No changes (the Urban District of West Mersea had been formed as a separate local authority in 1926). For the 1983 general election, the constituency was abolished, with the northern parts (comprising the majority) forming the bulk of the new constituency of
North Colchester. Southern areas were included in the new constituency of
South Colchester and Maldon.
1997–2010 • The Borough of Colchester wards of Berechurch, Castle, Harbour, Lexden, Mile End, New Town, Prettygate, St Andrew's, St Anne's, St John's, St Mary's, Shrub End, and Stanway.
Re-established as a Borough Constituency from parts of the abolished constituencies of South Colchester and Maldon (Berechurch, Harbour, New Town, Prettygate and Shrub End wards) and North Colchester (remaining wards). 2010–2024 • The Borough of Colchester wards of Berechurch, Castle, Christ Church, Harbour, Highwoods, Lexden, Mile End, New Town, Prettygate, St Andrew's, St Anne's, St John's, and Shrub End.
Local authority wards redistributed. Minor reduction in electorate, with Stanway ward being included in the new constituency of Witham. Current Further to the
2023 review of Westminster constituencies, which came into effect for the
2024 general election, the composition of the constituency is as follows (as they existed on 1 December 2020): • The City of Colchester wards of: Castle; Greenstead; Highwoods; Lexden & Braiswick (polling districts AQ, AS and AT); Mile End; New Town & Christ Church; Prettygate; St. Anne’s & St. John’s; Shrub End.
The revised contents closely correspond to the previous boundaries, with the exception of the Old Heath and The Hythe areas to the south east of the city centre, which are now included in Harwich and North Essex. ==Members of Parliament==