Heathland comprises vegetation with greater than 25% cover of ericaceous dwarf shrubs such as heather Calluna vulgaris or cross-leaved heath Erica tetralix and dwarf gorse (mostly western gorse Ulex gallii). Heathland may be distinguished by wet or dry forms. Dry heath is characterised by heather, bell heather Erica cinerea and western gorse. Wet heath is characterised by cross-leaved heath, heather, purple moor grass Molinia caerulea and bog mosses Sphagnum spp. However, the concept of heathland also encompasses a suite of ancillary habitats such as bog, flush, scrub, grass-heath mosaic, bare ground and rock outcrops. Together these create the diversity of micro-habitat that makes heathland a rich habitat for biodiversity. Notable rarities in this habitat include the chough, silver spotted blue, pillwort Pilularia globulifera, pale heath violet Viola lactea, marsh gentian Gentiana pneumonanthe and three-lobed water crowfoot Ranunculus tripartitus.

Much heathland is a product of centuries of human activity on poor, thin infertile soils. Such areas were often the residual "common land" of the village, available to the poor and landless for grazing, turf cutting, firewood gathering and supplies of sand and stone. Little was put back into the land lest others might profit from their neighbour's labours, so the gradual extraction of plant nutrients led to the further impoverishment of the soils. This environment permits the survival of a range of species free from the competition of strong-growing agricultural grasses.

There are approximately 900ha of heathland on the island, (1.2% of the land area) though large areas have been lost in the past century to agricultural reclamation and forestry. Particularly good examples of dry heath occur on Holyhead Mountain (within Glannau Ynys Gybi SSSI) and Mynydd Bodafon, whilst the less extensive wet heath is best seen on the common land at Fedw Fawr (within Arfordir Gogleddol Penmon SSSI) or at Cors Goch National Nature Reserve (notably within Graig Wen - Cors Castell SSSI).

Heathland is characteristically found on acid soils so the presence of heathland on limestone outcrops at Bwrdd Arthur, Bryn Offa and Mariandyrys (as at the Great Orme on the Welsh mainland) is a particular feature of note. This calcareous heath displays a bizarre mixture of acid loving species such as heather and bell heather alongside calcareous herbs such as rock-rose Helianthemum nummularium, thyme Thymus praecox and salad burnet Sanguisorba minor.

Coastal heath is perhaps the only truly "natural" heathland on the island, where the exposure to wind and salt precludes other vegetation. It is characterised by the presence of blue carpets of spring squill Scilla verna with buck's horn plantain Plantago coronopus and is often an important foraging area for chough due to the short sward and frequent bare erosion areas. Good examples can be seen at Penrhosfeilw common (Glannau Ynys Gybi SSSI) at Borth Wen, east of Rhoscolyn bay (Glannau Rhoscolyn SSSI) and north of the racing circuit at Aberffraw (Ty Croes SSSI).

The Anglesey Heathland Partnership was formed in January 2003 and comprises various conservation and countryside organisations. Members either manage heathland sites directly or support heathland management indirectly through their work. The Partnership works to the following terms of reference:

The Partnership has agreed to support the Aim and Objectives of the Anglesey Heathland Strategy. The members of the Anglesey Heathland Partnership are as follows: