Dorset County Council was first formed in 1888 by an act of government to govern the newly created administrative county of Dorset which had been based largely on the historic county borders. Dorset became a two-tier non-metropolitan county after a reorganisation of local government in 1974 and its border was extended eastwards to incorporate the former Hampshire towns of Bournemouth and Christchurch. Following a review by the Local Government Commission for England, Bournemouth and Poole each became administratively independent single-tier unitary authorities in 1997.