In these lists of mountains in Ireland, those within Northern Ireland, or on the Republic of Ireland – United Kingdom border, are marked with an asterisk, while the rest are within the Republic of Ireland. Where mountains are ranked by height, the definition of the topographical prominence used to classify the mountain (e.g. the change in elevation required between neighbouring mountains), is noted. In British definitions, a height of 600 metres (1,969 ft) is required for a mountain, whereas in Ireland, a lower threshold of 500 metres (1,640 ft) is sometimes advocated.