The East Riding of Yorkshire, or simply East Riding or East Yorkshire, is a county in Northern England. The name is traditionally and geographically a reference to the easternmost of the three subdivisions (called Thrydings or Ridings) of the traditional county of Yorkshire. The boundaries of the East Riding, the North Riding and the West Riding were historically treated as three separate areas for many cultural and legal purposes, such as having separate quarter sessions. In 1889 under the Local Government Act 1888, administrative counties were formed on the existing historic county boundaries in England, but in Yorkshire, given the vast size of the county area, three administrative county councils were created, based on the historic boundaries of the three Ridings. The East Riding County Council was the administrative local government and ceremonial county (Lieutenancy) area established for the area (based in Beverley); it remained in place for eighty-six years until being removed for new administrative tiers of local government.
Subsequent changes to the political designation of the area have followed. Despite sharing the same or similar name, none of the successor local council areas share the same geographical boundaries. The traditional geographic and historic cultural East Riding of Yorkshire covers a larger area than both the current ceremonial area and the intermittent and current local government administrative area councils.
At the 2011 United Kingdom census, the East Riding of Yorkshire population was 334,179.