The North York Moors is an upland area in north-eastern Yorkshire, England. It contains one of the largest expanses of heather moorland in the United Kingdom. The area was designated as a National Park in 1952, through the National Parks and Access to the Countryside Act 1949. Covering an area of 554 sq mi (1,430 km²), the National Park has a population of 23,380. It is administered by the North York Moors National Park Authority, which is based in Helmsley.