Mercia is one of the kingdoms of the Anglo-Saxon Heptarchy.

It is centered on the valley of the River Trent and its tributaries in the region now known as the English Midlands.

The name is a Latinization of the Old English Mierce or Myrce, meaning "border people".Mercia's neighbors included Northumbria, Powys and the kingdoms of southern Wales, Wessex, Sussex, Essex and East Anglia.The name Mercia is still in use today by a wide range of organizations, including military units, public, commercial and voluntary bodies; and occurs as a female given name.