The population of the borough at the 2021 census was 107,800,[5] of which over 86% (93,015) lived in the built-up area of Darlington itself.

[8][9] The enlarged borough was also reconstituted as a non-metropolitan district as part of the 1974 reforms, with Durham County Council once more providing county-level services to the town.

[12] Since 2016 the council has been a member of the Tees Valley Combined Authority along with Hartlepool, Middlesbrough, Redcar and Cleveland and Stockton-on-Tees.

Unlike Darlington, the other four districts in the combined authority had all been part of the county of Cleveland between 1974 and 1996.

Parts of the borough are covered by civil parishes, which form a second tier of local government for their areas.

[18] Political control of the council since the 1974 reforms has been as follows:[19] Lower-tier non-metropolitan district Unitary authority The role of mayor is largely ceremonial.