For the statesman commonly called Castlereagh, see Robert Stewart, Viscount Castlereagh

Castlereagh Borough Council is a Local Council in Northern Ireland. Unusually it has no natural Borough centre, consisting of a series of suburbs of Belfast in the Castlereagh Hills to the south-east of the City. The main centres of population are Carryduff, 8km south of Belfast City Centre and Dundonald , 8km east of it, and the population totals nearly 66,500.

The Castlereagh Borough Council area consists of 4 electoral areas: Castlereagh Central, South, East and West. In the last elections in 2001 23 members were elected from the following political parties: 9 Democratic Unionist Party (DUP), 5 Ulster Unionist Party (UUP), 4 Alliance Party, 2 Social Democratic and Labour Party (SDLP), 1 Progressive Unionist Party (PUP) and 1 Independent. The current Mayor is Councillor Joanne Bunting (DUP)and the Deputy Mayor is Councillor David Drysdale (UUP).

The next election is due to take place in May 2005.

Castlereagh and the City of Kent, Washington State signed up as sister cities partners on 1 August 2000.

In elections for the Westminster Parliament the area is split between the East Belfast constituency, the South Belfast constituency and the Strangford constituency. It has previously also had a section included in the North Down constituency

See Also: Local Councils in Northern Ireland