The Local Board of Milnerton was constituted on 24 December 1925 in terms of Proclamation No 243, 1925 under provision of the Local Board Ordinance No 11, 1921 (Province of the Cape of Good Hope Official Gazette, No 1011, 31 December 1925). The Board ceased to exist at the end of June 1955 when a Municipal Council was established.

The Municipality of Milnerton was constituted on 1 July 1955 in terms of Proclamation No 30 dated 22 February 1955 under provision of Ordinance No 19, 1955 (Province of the Cape of Good Hope Official Gazette No 2746, 11 March 1955).

On 1 February 1995 all local authorities were dissolved and each one was replaced by a Transitional Metropolitan Substructure. The new Cape Metropolitan Council was created which included all the substructures (Province of Western Cape Provincial Gazette, No 4929, Proclamation No 18).

On 28 May 1996 the substructures were dissolved and a new Blaauwberg Substructure was created, remaining part of the Cape Metropolitan Council (Province of Western Cape Provincial Gazette Extraordinary, No 5051, 28 May 1996). Local elections were held for these structures on 29 May.