The Municipality of Mossel Bay was constituted on 5 July 1865 in terms of Proclamation No 59 of 1865 under provision of Ordinance No 9 of 1836.

In terms of the Local Government: Municipal Structures Act, 1998 (Act 117 of 1998) the existing Municipality of Mossel Bay together with the municipalities of Great Brak River and Herbertsdale, the Friemersheim Transitional Council, and the transitional representative councils of Mossel Bay and Outeniqua, was disestablished and the Mossel Bay Local Municipality established (Province of Western Cape Provincial Gazette Extraordinary No 5592, 22 September 2000, Provincial Notice No 500, 22 September 2000). The Mossel Bay Local Municipality forms part of the larger Garden Route District Municipality.

According to the Town Clerk all archives, with the exception of council and general standing committees minutes older than thirty years, were destroyed during a fire in 1961.

On 1 January 1980 the Divisional Councils of George, Knysna and Mossel Bay were re-constituted together to form the amalgamated Divisional Council of Outeniqua.

The following local areas committees were instituted: Boggomsbaai, Brenton, Buffels Bay, Herolds Bay, Hoekwil, Keurboomstrand, Little Brak River, Nature’s Valley, Reebok, Tergniet, Wilderness, Wilderness Heights and Wittedrift.

On 31 March 1989 portions of the Divisional Council Areas of Outeniqua and Langeberg were established as the South Cape Regional Services Council. The other portions of the Divisional Council Areas of Outeniqua and Langeberg together with the Divisional Council Area of Klein Karoo-Langkloof were established as the Klein Karoo Regional Services Council.

In terms of Proclamation No 152 of 15 December 1995 (Establishment of Rural Local Government Structures) the South Cape Regional Services Council was disestablished and replaced by the South Cape District Council (Province of Western Cape Provincial Gazette Extraordinary No 5004 of 15 December 1995).

On 22 September 2000 the South Cape District Council, Klein Karoo District Council and various other councils were disestablished and the Garden Route/Klein Karoo (later Eden, then Garden Route) District Municipality was established in terms of sections 12 and 14 of the Local Government: Municipal Structures Act 1998 (Province of Western Cape Provincial Gazette No 5592 of 22 September 2000, Provincial Notice No 497 of 22 September 2000).

The first meeting of the Local Board of Hartenbosch was held on 19 December 1973.

During 1974 the Municipality of Hartenbos was constituted under the provisions of the Municipal Ordinance No 20 of 1974 (volume 3/HRB 1/1/1).

In terms of the Local Government Transition Act, 1993 (Act 209 of 1993) the local government bodies within the Mossel Bay Forum Area, namely the Mossel Bay Municipality, Hartenbos Municipality, D’Almeida Management Committee, Kwanonqaba Town Council, the Klein Brakrivier, Reebok and Tergniet Local Council and Boggomsbaai Local Council, was dissolved with effect from 1 February 1995 and a transitional local council under the name Municipality of Mossel Bay established (Province of Western Cape Provincial Gazette Extraordinary No 4925, 31 January 1995, Proclamation No 25, 30 January 1995).

On 5 January 1858 the division of Mossel Bay was subdivided into six districts for divisional council purposes under provision of Act No 12 of 1857 (Cape of Good Hope Government Gazette No 2893, 8 January 1858, Proclamation of 5 January 1858).

On 1 January 1980 the Divisional Council of Mossel Bay was reconstituted together with the Divisional Councils of George and Knysna to form the amalgamated Divisional Council of Outeniqua (The Province of the Cape of Good Hope Official Gazette No 4061, 20 July 1979, Proclamation No 174, 18 July 1979).

The Village Management Board of Great Brak River was established on 1 December 1943 under provision of section one (1) of Ordinance No 11, 1921 in terms of Proclamation No 135 of 1943 (The Province of the Cape of Good Hope Official Gazette, No 2075, 3 December 1943). The Board ceased to function with effect from 1 January 1975 when the Municipality of Great Brak River was established.

The Municipality of Great Brak River was established with effect from 1 January 1975 under the provisions of Section 5(1) and 8(1) of the Municipal Ordinance No 20, 1974 in terms of Proclamation No 414, 1974 (Province of the Cape of Good Hope Extraordinary Official Gazette, No 3809, 3 December 1974).

In terms of the Local Government: Municipal Structures Act, 1998 (Act 117 of 1998) the existing Municipality of Great Brak River together with the municipalities of Mossel Bay and Herbertsdale, the Friemersheim Transitional Council, and the transitional representative councils of Mossel Bay and Outeniqua, was disestablished and the Mossel Bay Local Municipality established (Province of Western Cape Provincial Gazette Extraordinary No 5592, 22 September 2000, Provincial Notice No 500, 22 September 2000). The Mossel Bay Local Municipality forms part of the larger Eden (now Garden Route) District Municipality.