[9] Under the Local Government (Scotland) Act 1973, local government counties, cities and their subordinate councils (including burghs and parishes) were abolished and replaced by an upper tier of regions each of which contained a number of districts except for the Western Isles, Shetland Islands and Orkney Islands where each had a single-tier authority created which exercised all the powers elsewhere split across two levels of local government.
Two of the three islands authorities - Orkney and Shetland - changed their legal nature but continued with boundaries identical to the earlier counties; the Western Isles area was previously split between Inverness-shire and Ross and Cromarty.
Although Scottish Councils are now unitary in nature none is officially termed a unitary authority, as in the United Kingdom that phrase is specific to English local government legislation.
One region and various of the districts created in 1975 had areas similar to those of earlier counties.
Apart from their legal nature, the three islands authorities continued with their previous boundaries and most of their powers unaltered.