[2] The name Plenmeller is first attested in 1255–56, with diverse spellings appearing: Plenmeneure, Plenmenewre, and Playnmalevere.

The name is thought to come from the Brittonic language, comprising the words that in modern Welsh are blaen ("top"), moel ("bare"), and bre ("hill").

Historically, Plenmeller was a township, also incorporating Unthank, within the ancient parish of Haltwhistle.

More recently coal has been extracted by open cast methods on Plenmeller Common and 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, was substantially remodelled and extended in 1815.

[10] The village is now served by Haltwhistle railway station on the Tyne Valley line.