The boundaries of the Scottish Parliament's constituencies and regions could be redrawn.
The Holyrood boundary review will not affect the number of MSPs
A review of all voting area borders, with the exception of the Orkney and Shetland Islands, has been announced by the Boundary Commission for Scotland.
The purpose is to make sure MSPs represent a similar number of people.
The population of some Highland constituencies has risen to more than 70,000, compared to less than 50,000 in the Central belt.
'Scope for change'
The number of MSPs will remain the same, even though a recent revision of Westminster constituencies saw the number of Scottish MPs reduced from 72 to 59.
The Boundary Commission's first proposals will be published next spring, followed by a lengthy consultation which may include public inquiries.
Final recommendations will be submitted to the Secretary of State for Scotland by June 2010 - about a year before the next Holyrood election.
Commission Secretary Bob Smith told the BBC: "The reason for the review is to make things equitable and there is scope for change."
The average number of registered voters in each constituency is expected to end up about 54,500.
Under existing legislation, the Orkney and Shetland Islands, which have the lowest populations, are excluded from constituency reviews.
However, the boundaries of the Western Isles, where less than 22,000 voters live, will be reassessed.