Arthur's Seat is the main peak of the group of hills which form most of Holyrood Park, described by Robert Louis Stevenson as "a hill for magnitude, a mountain in virtue of its bold design". It is situated in the centre of the city of Edinburgh, about a mile to the east of Edinburgh Castle. The hill rises above the city to a height of 250.5 m (822 ft), provides excellent panoramic views of the city, is relatively easy to climb, and is popular for hillwalking. Though it can be climbed from almost any direction, the easiest and simplest ascent is from the east, where a grassy slope rises above Dunsapie Loch.
Many claim that its name is derived from the myriad legends pertaining to King Arthur, such as the reference in Y Gododdin. Some support for this theory may be provided by the fact that several other hilltop and mountaintop features in Britain bear the same or similar names, such as the peak of Ben Arthur (The Cobbler) in the western highlands, sometimes known as Arthur's Seat, and Arthur's Chair on the ridge called Stone Arthur in the Cumbrian lake district. There is no traditional Scottish Gaelic name for Arthur's Seat in Edinburgh but William Maitland proposed that the name was a corruption of Àrd-na-Said, implying the "Height of Arrows", which over the years became Arthur's Seat (perhaps via "Archer's Seat"). Alternatively, John Milne's proposed etymology of Àrd-thir Suidhe meaning "place on high ground" uncomfortably requires the transposition of the name elements.[source]