This is a list of P600 mountains in Britain and Ireland by height. A P600 is defined as a mountain with a topographic prominence above 600 m (1,969 ft), regardless of elevation or any other merits (e.g. topographic isolation); this is a similar approach to that of the Marilyn, Simms, HuMP and TuMP British Isle mountain and hill classifications. By definition, P600s have a height above 600 m (1,969 ft), the requirement to be called a "mountain" in the British Isles. The "P" terminology is an international classification, along with P1500 Ultras. P600 and "Majors" are used interchangeably.
As of October 2018, there were 120 P600s in the British Isles: 81 in Scotland, 25 in Ireland, 8 in Wales, 4 in England, 1 in Northern Ireland, and 1 in the Isle of Man. The 120 P600s contained 54 of the 282 Scottish Munros, and 10 of the 34 Non-Scottish Munros (or Furths), all of which have heights above 3,000 feet (914.4 m), and are sometimes called the "Super-Majors". The list also contained the highest mountains in Scotland, Wales, Ireland, and England.