Mercia originally comprised the border areas (modern Staffordshire, Derbyshire, Nottinghamshire, and northern West Midlands and Warwickshire) that lay between the districts of Anglo-Saxon settlement and the Celtic tribes they had driven to the west.

What is Mercia called today?

Mercia was one of the Anglo-Saxon kingdoms of the Heptarchy. It was in the region now known as the English Midlands. ... Settled by Angles, their name is the root of the name 'England'.

When did Mercia cease to exist?

Mercia was conquered by the Vikings, and its king driven into exile, in 873/4, after which it ceased to exist as an independent kingdom.