The highest summit in Shetland, Ronas Hill lies between the sea lochs of Ronas Voe, to the west, and Colla Firth, to the east, in the Northmavine district of the Shetland Mainland. This hill rises to a height of 450m (1476 feet), 2¾ miles (4.5 km) west of the settlement of North Collafirth. At its summit there are the remains of an ancient chambered cairn as well as spectacular views westwards to the Atlantic and eastwards to Yell Sound. There is also an Ordnance Survey primary triangulation pillar installed 1948-49. Geologically, the hill represents part of a magma chamber, a remnant of an ancient volcano. Today, the environment here is Sub-Arctic, strewn with wind-rounded granite boulders and frost-shattered rock fragments known as 'fellfield' which is colonised by rare Alpine plant species such as Alpine lady's mantle (Alchemilla alpina), spiked woodrush (Luzula spicata) and mountain azalea.
