Coal mining dominated the history of the area in recent times. Employment at Plenmellor colliery reached its peak in the early 1920s. When the colliery closed in 1932 it caused widespread hardship in the area. More recently coal has been extracted by open cast methods on Plenmellor Common and the land then returned to a more natural landscape.
Unthank Hall is a Grade II listed mansion house, now serving as commercial offices, situated on the southern bank of the River South Tyne. The house, which was built in the 16th century, incorporating an ancient pele tower, and was substantially remodelled and extended in 1815. The Hall was later rebuilt between 1862 and 1865. Much of the 1865 house has since between demolished and only the central gables and entrance porch survive.
Plenmellor was a township in the ancient parish of Haltwhistle and became a separate civil parish in 1866. In 1955 it was abolished as a civil parish and became part of the newly-formed civil parish of Plenmellor with Whitfield (or Plenmeller with Whitfield).