Prior to the national elections in Iceland on 10 May 2003, changes were made to the constituencies so that the country is now divided into six constituencies: the northwest and northeast, south and southwest districts, Reykjavík north and Reykjavík south.
According to constitutional provisions on constituencies, which were adopted in June 1999, they must number at least six and no more than seven. The constituency boundaries are decided by law; however, the national electoral committee may be authorised to draw the boundaries in Reykjavík and the vicinity. Following each election to Althingi, if the number of registered voters represented by each parliamentary seat, including equalisation seats, in any constituency is less than half that of those in another constituency, the national electoral committee shall adjust the number of parliamentary seats in the constituencies to reduce this difference. The number of seats in each constituency must, however, be at least six. Changes to the constituency boundaries and arrangements for allocating seats in parliament, as prescribed by law, can only be made with the approval of two-thirds of votes cast in the Althingi. Prior to this Iceland was divided into eight constituencies, under arrangements which had prevailed since 1959.