About Middlesex

Middlesex (; abbreviation: Middx) is a historic county in southeast England. Its area is almost entirely within the wider urbanised area of London and mostly within the ceremonial county of Greater London, with small sections in neighbouring ceremonial counties. Three rivers provide most of the county's boundaries; the Thames in the south, the Lea to the east and the Colne to the west. A line of hills forms the northern boundary with Hertfordshire. The county's name derives from its origin as the Middle Saxon Province of the Anglo-Saxon Kingdom of Essex, with the county of Middlesex subsequently formed from part of that territory in either the ninth or tenth century, and remaining an administrative unit until 1965.