The constituency covers the northern edge of Greater Glasgow, and includes commuter towns on the North Clyde and Croy railway corridors. Since 1974 the constituency has been represented by all four of the main political parties in Scotland.
The historic constituency was created under the House of Commons Act 1949, and first used in the 1950 general election. As created in 1950, the constituency was one of two covering the county of Dunbarton. The other was West Dunbartonshire. The two new constituencies replaced the earlier constituencies of Dunbartonshire and Dumbarton Burghs. East Dunbartonshire covered the Cumbernauld, Kirkintilloch, and New Kilpatrick districts of the county and the burghs of Clydebank, Kirkintilloch, and Milngavie. For the 1951 general election the constituency boundaries were adjusted to take account of a change to the boundaries of the burgh of Clydebank. The results of the First Periodical Review of the Boundary Commission were implemented for the 1955 general election, but there was no change to the boundaries of East Dunbartonshire, and the boundaries of 1951 and 1955 were used also in the general elections of 1959, 1964, 1966 and 1970. The results of the Second Periodical Review were implemented for the February 1974 general election. The review took account of population growth in the county of Dunbarton, caused by overspill from the city of Glasgow into the new town of Cumbernauld and elsewhere, and East Dunbartonshire became one of three constituencies covering the county. East Dunbartonshire now covered the Kirkintilloch and Cumbernauld districts of the county and the burghs of Bearsden, Cumbernauld, and Kirkintilloch, but it lost Clydebank and Milngavie to the new constituency of Central Dunbartonshire. These boundaries were used also for the general elections of October 1974 and 1979. In 1975, under the Local Government Act 1973, Scottish counties were abolished in favour of regions and districts and islands council areas, and the county of Dunbarton was divided between several districts of the new region of Strathclyde. The Third Periodical Review took account of new local government boundaries, and the results were implemented for the 1983 general election.
The constituency of 1950 to 1983 has an unusual electoral history, in that in two consecutive general elections it was gained by the party in third place at the previous election. In October 1974 the SNP leapfrogged Labour to defeat the Conservatives, and in 1979 Labour leapfrogged the Conservatives to beat the SNP. Furthermore, the constituency went the opposite way to the nation in two consecutive changes of government. In February 1974, the Conservatives gained it from Labour, though losing nationally, while in 1979 Labour regained the seat from the SNP, though losing nationally. Apart from Ynys Môn in Wales, East Dunbartonshire is the only seat to have been represented by the three main parties and the nationalists.
Elections in the 1970s
The October 1974 result was particularly unusual since it produced both the smallest majority in the country at that election, and the closest three-way result since 1945.
