The City of Durham was first given the right to return Members to Parliament by an Act of Parliament in 1678, the last new borough but one to be enfranchised before the Great Reform Act of 1832. It was the only borough in County Durham, the county also having been unrepresented until the same Act of Parliament, which created two MPs for the county and two for the city. Both constituencies were frequently referred to simply as Durham, which can make for some confusion.
The constituency as constituted in 1678 consisted only of the city of Durham itself, though this included its suburbs which were within the municipal boundary. The right to vote was held by the corporation and the freemen of the city, many of whom were not resident within the boundaries. Unlike the situation in many small rotten boroughs, the corporation had no jurisdiction over the creation of freemen: freemen were generally created by connection with companies of trade, either by apprenticeship or by birth (by being the son of an existing freeman), though the common council of the city had a power to create honorary freemen.
The creation of honorary freemen with the specific intention of swaying elections was a common abuse in a number of boroughs in the 18th century, and at the Durham election of 1762 became sufficiently controversial to force a change in the law. The election was disputed because 215 new freemen, most of them not resident in the city, had been made after the writ for the election was issued. The existing freemen petitioned against this dilution of their voting rights, the candidate who had been declared elected was unseated by the Commons committee which heard the case, and the following year an Act of Parliament was passed to prevent any honorary freeman from voting in a borough election within twelve months of their being accorded that status.
Through having a freeman franchise the electorate was comparatively numerous for the period, though comprising only a small fraction of the city's population; at the time of the Reform Act there were between 1,100 and 1,200 freemen in total, of whom 427 were resident and 558 lived within seven miles, while the total population of the borough was 9,269. The Lambton and Tempest families were influential, and were generally able to secure election, but fell far short of the sort of control common in pocket boroughs.
The city retained both its MPs under the 1832 Reform Act, with its boundaries adjusted only very slightly, although as elsewhere the franchise was reformed. The Reform Act 1867 extended the boundaries to include part of Framwellgate parish which had previously been excluded. Under the Redistribution of Seats Act 1885, the borough's representation was reduced at the from 1885 general election to a single MP. In the boundary changes of 1918, the borough was abolished, but a division of County Durham was named after the City.
From 1918, Durham City was included in a county constituency officially called The Durham Division of (County) Durham, consisting of the central part of the county. Until 1974 it included the town of Hetton-le-Hole and between 1950 and 1974 that of Spennymoor, as well as the rural districts in between, in which coal mining was the principal industry. The Durham county constituency from 1974 to 1983 included Durham itself, the Durham Rural District except Brancepeth and Sedgefield Rural District. In the 1983 boundary changes, the constituency officially acquired the unambiguous City of Durham name for the first time and its boundaries were realigned to match the new City of Durham local government district.
The constituency corresponds to the former City of Durham local government district and as such includes a number of surrounding villages and suburbs as well as Durham itself, the largest of these are Brandon, Coxhoe, Bowburn, Framwellgate Moor, Sherburn and Ushaw Moor. The seat extends as far west as Waterhouses and as far east as Ludworth. The seat has traditionally been dominated by Labour, with support particularly strong in those villages historically connected to County Durham's mining industry. Durham is famous as an educational centre, for Durham University and the feepaying preparatory school, Chorister School where Tony Blair was educated. The city centre is more inclined to the Liberal Democrats. Like many other university cities such as Cambridge and Oxford, in the 2005 election it swung strongly towards the Liberal Democrats, one possible reason being these cities' sizeable student population who were viewed as being hostile to Labour's policies on areas such as top-up fees and the Iraq War. The Liberal Democrats were able to reduce Labour's majority by over 10,000 votes, although they were still unable to gain the seat from Labour, as was the case in the 2010 election.