Lotharingia was a short-lived kingdom in western Europe, the aggregate of territories belonging to Lothair, King of Lotharingia (reigned 855-869), who received it in 855 from his father, Lothair I (795-855), Holy Roman Emperor. The territory was the northern section of the division of Carolingian lands that had been effected at the Treaty of Verdun, 843. After Lothair's death his lands were further divided between the Kingdom of the East Franks and the Kingdom of the West Franks, in the Treaty of Mersen, 870.

Strictly speaking, there were no Lotharingians as a unified ethnic group. Broadly speaking, Lotharingia comprised the present-day:

• Netherlands
• Belgium
• Luxembourg
• North Rhine-Westphalia (Germany)
• Rhineland-Palatinate (Germany)
• Saarland (Germany)
• Lorraine (France)
• Alsace (France)

The name survives today in the name derived from it: Lorraine (in German: Lothringen). Lotharingia did not survive its king; it dissolved in violence and local warfare. Henry the Fowler gained control over the divided lands and granted them to his brother, Saint Bruno, archbishop of Cologne. In 959 Bruno effected the long-lasting split of the territories, under two dukes, as the duchies of Upper Lorraine and Lower Lorraine. Upper Lorraine became the duchy of Lorraine, the nucleus of which survived until 1766. Upper Lorraine was the object of territorial disputes between France and Germany for a thousand years.

The Duchy of Lower Lorraine did not withstand the centripetal forces of the 10th century; it fragmented into duchies and counties:

• Brabant
• Limburg
• Jülich
• Cleves
• Berg
• County of Bouillon
• County of Hainaut
• Prince-Bishopric of Liège

See also: European region Lotharingia (German/French)