Image: Wikimedia Commons

Middlesex

Historic county of England

Cityhistoric county of England former administrative territorial entity administrative countyQ19186

Also known as Middx

Country: United Kingdom
Located in: Greater London(since 1965)
, England(until 1965)
Population: 2,234,543(1961)
1
Sources
1.visionofbritain.org.uk/unit/10061441/cube/TOT_POP
View statement on Wikidata ↗
Area: 601.7 km²
Postal code: EN
, HA
, TW
+1 more

Overview

From Wikipedia, the free encyclopedia · Read full article · Text CC BY-SA 4.0

Middlesex is one of the historic counties of England. The county boundaries largely followed three rivers: the Thames in the south, the Lea to the east and the Colne to the west, with a line of hills forming its northern boundary with Hertfordshire. Its former area now lies almost entirely in the ceremonial county of Greater London, with smaller parts in the counties of Hertfordshire and Surrey. The county is the second smallest of the historic counties of England, after Rutland.

Overview

All data

66 statements · 15% with external sources · numbers in brackets are citations

Flag: flag of Middlesex
Shares border with: Buckinghamshire
Hertfordshire
Essex
Kent
Surrey
County of London(1889–1965)
Different from: Middlesex
Catalog code: MSX catalog: Historic Counties Standard
Part of: England
Located in the present-day administrative territorial entity: Greater London(since 1965)
Surrey applies to part: Spelthorne
Hertfordshire applies to part: Potters Bar
Dissolved: April 1, 1965 cause: London Government Act 1963
Significant event: boundary change(November 1, 1900) applies to part: South Hornsey · gave up territory to: County of London · cause: London Government Act 1899
boundary change(November 1, 1900) gained territory from: County of London · applies to part: Alexandra Park · cause: London Government Act 1899
boundary change(March 21, 1889) applies to part: Metropolitan Board of Works area · gave up territory to: County of London · cause: Local Government Act 1888
Territory overlaps: Metropolitan Board of Works area(1855–1889)
Metropolitan Police District
Legislative body: Middlesex County Council(1889–1965)
Middlesex Quarter Sessions(until 1889)

On other databases

30 identifiers linking Middlesex across the web's reference databases

51.5400, -0.2700OpenStreetMap ↗

Data quality

statements

15%

externally sourced

Source last edited September 5, 2026. AIDB refreshes this page daily.

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AIDB. (2026). Middlesex (Q19186). Retrieved from https://aidb.si/e/middlesex-Q19186