Leinster (/ˈlɛnstər/ LEN-stər; Irish: Laighin [ˈl̪ˠəinʲ] or Cúige Laighean [ˌkuːɟə ˈl̪ˠəinˠ]) is one of the provinces of Ireland, situated in the southeast and east of Ireland. The province comprises the ancient Kingdoms of Meath, Leinster and Osraige. Following the 12th-century Norman invasion of Ireland, the historic "fifths" of Leinster and Meath gradually merged, mainly due to the impact of the Pale, which straddled both, thereby forming the present-day province of Leinster. The ancient kingdoms were shired into a number of counties for administrative and judicial purposes. In later centuries, local government legislation has prompted further sub-division of the historic counties.

  Teachtaí Dála
  Total19,801 km2 (7,645 sq mi)
  Total2,630,720 (1st)
  Density126.5/km2 (328/sq mi)
Time zoneUTC±0 (WET)
  Summer (DST)UTC+1 (IST)
Eircode routing keys
Beginning with A, C, D, N, R, W, Y (primarily)
Telephone area codes01, 04x, 05x, 090 (primarily)
ISO 3166 codeIE-L
Patron Saint: Brigid[3] a. ^ Leinster contains the entirety of the Dublin constituency and parts of the South and Midlands–North-West constituencies; Leinster contains 44.4% of the population of the Midlands–North-West constituency and 32.3% of the population of the South constituency.[4]

Leinster has no official function for local-government purposes. However, it is an officially recognised subdivision of Ireland and is listed on ISO 3166-2 as one of the four provinces of Ireland. "IE-L" is attributed to Leinster as its country sub-division code. Leinster had a population of 2,630,720 according to the preliminary results of the 2016 census, making it the most populous province in the country.[2] The traditional flag of Leinster features a golden harp on a green background.