unitary authority, geographic and historic county of Shropshire, west-central England, in the east-central part of the county. The unitary authority, drained in the south by the River Severn, is a plain covered by glacial drift soils in the north. Historically important iron-manufacturing industrial villages are scattered along the Shropshire Hills in the south.

The unitary authority takes its name from the Wrekin, which is a 1,334-foot (407-metre) hill near its southwestern border, and from the adjacent town of Telford. The planned new town of Telford extends across the industrial villages (including Dawley, Madeley, Ironbridge, Coalport, Coalbrookdale, Wellington, and Oakengates) and encompasses nearly one-third of the unitary authority's total area. Historical firsts of the area's iron industry are the smelting of iron with coke (1709), the first iron bridge (cast in Coalbrookdale in 1774 and built at Ironbridge in 1779), and the first iron boat (1787); all are commemorated in a museum of industrial archaeology at Coalbrookdale. Contemporary iron foundry manufactures of the villages include steel furniture, automotive components, and stoves. The northern part of the unitary authority is mostly rural and agricultural, and cattle and cereals are raised near the northeastern market town of Newport. Telford is the administrative centre. Area 112 square miles (290 square km). Pop. (2005 est.) 161,600.