Skiddaw Group SSSI is a site of special scientific interest in the Lake District High Fells, England. Its shape is approximately a rough circle centred near Great Calva, with an area of . The high ground creates a watershed between the "Caldew Operational Catchment" with water flowing north towards Carlisle, and the "Ellen and West Coast" and "Derwent Operational Catchments" flowing towards the west coast at Workington and Maryport.
The SSSI is designated for its flora and fauna, and for its geology. The geology includes the Skiddaw Group of sedimentary rock formations, and the Caldbeck Fells former mining area. Fells above include High Pike, Carrock Fell, Knott, Great Calva, and Bowscale Fell. The highest peaks are in the Skiddaw area, including Skiddaw itself, Long Side, Carl Side, Little Man, Lonscale Fell and, further east, Blencathra.
The SSSI is divided into "units" which are used as the level of geographic detail for reporting overall features and conditions. Each unit is identified by the Ordnance Survey grid reference at the centre of the unit, its area in hectares, the date it was last surveyed, and the drainage catchment it is located in. For example "Bassenthwaite Common", which is unit 27, is nearly centred at in the "Dash beck" catchment. The habitat is there is "dwarf shrub heath" which, when surveyed in November 2010, was in an "unfavourable – recovering" condition.
Skiddaw Forest.
Skiddaw Forest is the ancient name of an expanse of land to the east of Skiddaw summit, with the word "forest" referring here to a medieval pattern of land ownership. In 2024 the forest area within the Underskiddaw civil parish area, essentially SSSI units 30 and 31 together with the summits of Skiddaw and Great Calva, was purchased by Cumbria Wildlife Trust as a nature reserve. The long term biodiversity and rewilding goals include encouraging tree growth to create tracts of temperate rainforest, and restoring peatlands.
Unit 30, "Skiddaw Forest West", was assessed in 2021 as having "favourable" conditions for invertebrate and breeding bird features, but "unfavourable – recovering" blanket bog and upland dry heath habitats. Conditions in unit 31, "Skiddaw Forest East" were assessed as "favourable" in 2021.
Caldbeck Fells mines.
The SSSI designation includes a number of sites of former mines, noted today for the presence of minerals in spoil heaps and erosion sites.
Spoil heaps at Red Gill Mine () include rare, crystallised lead sulphates, carbonates and phosphates. An adjacent mine at Roughtongill () reveals supergene minerals including copper and zinc varieties. English Heritage undertook a detailed survey of Roughtongill in 2001 and reported on its history and archaeology.
Dry Gill Lead Mine () has a unique form of mimetite, known as 'campylite'. Natural England surveyed the site (SSSI Unit 10) in 2022 and found the exposed mineral veins had been damaged by collectors in the past but not recently. Burdell Gill () "is of national importance as the only relatively abundant source of the rare arsenic mineral, pharmacosiderite, in Britain." A vein at Wet Swine Gill () includes stibnite and fuloppite but the 2022 survey (SSSI Unit 2) found that geological specimen collecting continued to cause damage. In the Carrock Mine – Brandy Gill spoil heaps () the mineralisation is tungsten-rich. The Carrock Tungsten Mine () and Carrock End Copper Mine are Scheduled Monuments.
There are other mine sites not mentioned in the SSSI designation, such as in the wider Grainsgill area (), near to Carrock mine. A 2021 survey in that area (SSSI Unit 8) observed "ordovician igneous geological features". Breafell lead mine () was downstream from Redgill and Roughtongill on the Dale Beck, a tributary of the Whelpo. Driggith lead mine was downstream from Drygill mine. Sandbeck lead and copper mine () was north east of High Pike.
Caldew operational catchment.
The Skiddaw Group SSSI includes the headwaters of the "Whelpo (Cald) Beck" and "Caldew (upper)" 'water bodies' (catchments). These are part of the "Caldew operational catchment".
The "Whelpo Beck" catchment includes Brae Fell (), and the former mine sites at Red Gill and Roughtongill. When surveyed by Natural England in 2010, both mine sites (SSSI Units 3 and 11) were showing some signs of collector activity and erosion but were not considered to be under threat. The "dwarf shrub heath" habitats were surveyed in 2022 (SSSI Units 23 – Roughton Gill; 25 – Caldbeck North; and 26 – Brae Fell). They were all depleted by heavy grazing. Patches of bilberry were observed on Brae Fell.
The "Caldew (upper)" catchment accounts for 40% of the total area of the SSSI and the majority of its assessment units. The River Caldew flows there between the Blencathra uplands in the south-east of the SSSI, and the Skiddaw and Caldbeck Fells uplands to the west and north. The catchment includes Great Calva () and Carrock Fell (). Around the edge of the catchment, Lonscale Fell, Skiddaw, Skiddaw Little Man, and Bowscale Fell form watersheds with the catchments in the "Derwent Operational Catchment" area. It includes the former mine sites at Dry Gill Mine, Carrock Mine-Brandy Gill, Burdell Gill and Wet Swine Gill. It also includes Bowscale Tarn (), one of two glacial tarns in the SSSI, where quillwort isoetes lacustris, shoreweed littorella uniflora and water lobelia lobelia dortmanna have been found.
Heather moor predominates on sloping ground north and west of the River Caldew across several catchments. The east-facing slopes of Skiddaw, Little Man and Jenkin Hill exhibit degraded moss heath. Juniperus communis scrub, which is a nationally rare habitat, is most extensive on the steep, rocky south-facing slopes of Carrock Fell ().
Derwent management catchment.
The Skiddaw Group SSSI includes headwaters of the "Derwent management catchment", consisting of the "Ellen (upper)" catchment, which flows towards Maryport, and a number of catchments flowing towards Workington:
The "Ellen (upper)" catchment is at the north of the SSSI in the Uldale Fells. It is bounded by Longlands Fell, Lowthwaite Fell, Little and Great Sca Fells, Meal Fell and Great Cockup. Great Cockup () is known for fossils of dendroid graptolites. Tremadoc–Llanvirn geology is visible in the crags around Great Cockup. The heathland lacks species diversity and shows signs of heavy grazing. For catchment management purposes, the main water body is the Dale Gill which rises between Great and Little Cockup. The River Ellen's headwaters, with numerous small tributaries, drain the Uldale Fells and join Dale Gill beyond the SSSI boundary.
The SSSI includes the headwaters of the "Dash Beck" catchment, including short lengths of Dash Beck itself, and of a number of its tributaries. The part of the catchment within the SSSI stretches from Great Sca Fell in the north-east to Ullock Pike away in the south-west, with the Whitewater Dash waterfall () where the beck crosses the catchment midway between the two. The area includes Bakestall where empetrum nigrum is the dominant dwarf-shrub. It also includes Broad End which has "the best developed example [of montane moss-grass heath in West Cumbria] at about " elevation. There are two monitoring units in the "Dash beck" catchment: "Uldale South" (SSSI Unit 19, ) has low species diversity with some areas recovering; "Uldale North" (SSSI Unit 18, ) includes calluna vulgaris, vaccinium spp, empetrum nigrum and erica tetralix but the sites are fragmented where they should be continuous. In the north-east of the catchment, the watershed is marked by Knott, Great Sca Fell, Meal Fell, and Great Cockup.
The "Glenderaterra Beck" catchment includes "Lonscale Fell" (SSSI Unit 29, , surveyed 2024) and "Blencathra North West" (SSSI Unit 32, , surveyed 2019). Lonscale Fell ecology included some bracken and limited cover of ericoid shrubs in its "acidic grassland with bilberry" habitats. Blencathra North West had "blanket bog with abundant hare's-tail cotton grass and deer grass over locally abundant bog mosses".
There is a small area of Juniperus communis scrub in "Glenderamackin u/s Troutbeck" on The Tongue (). The same catchment includes Scales Tarn (Blencathra), one of the two glacial tarns in the SSSI. The tarn has "low nutrient levels and [is] inherently species-poor." The area around the tarn has in the past been subject to heavy grazing. Mungrisdale East (SSSI Unit 35, ) includes hare's-tail cottongrass, abundant sphagnum and a good population of serrated wintergreen. Young Wood (SSSI Unit 38, ) is protected by fencing to keep grazing animals away and the oak woodland is recovering.
Related activities.
Special Area of Conservation.
Skiddaw Group SSSI is a component of the Lake District High Fells, a Special Area of Conservation. The SAC covers a number of SSSIs but, within the Skiddaw Group, the SAC documentation identifies a range of habitats:
Cumbria Local Nature Recovery Strategy.
Local Nature Recovery Strategies (LNRS) are a UK government response to declining biodiversity. The local strategies are established to agree priorities and propose actions to reverse the decline. The Cumbria Local Nature Recovery Strategy was developed following initial "Vision and Priority" workshops held in March 2024, with further consultation during 2025. The strategy includes the development of an interactive habitat map. The map shows where habitats need enhancing or, in worse cases, restoring. For example SSSI Unit 22 "Carrock Fell" includes an area of "moorland, heathland and montaine" habitat which would benefit from enhancement. However the south west edge of the unit is in worse condition so would need restoration.
United Kingdom Biodiversity Action Plan.
The United Kingdom Biodiversity Action Plan identified a range of priority habitats which occur across the UK. The Skiddaw Group SSSI has large areas of "grass moorland" and "upland heath", together with more fragmented areas of "blanket bog". For example, the upland areas around Bannerdale Beck (SSSI Unit 35) contain of blanket bog, split across several smaller sites. More detailed mapping from DEFRA and the UK government open data resource shows the same areas of blanket bog but additionally shows areas where the habitat could be restored, where it could potentially be created, and where smaller areas could be used to re-join existing fragmented ones.
Geological Conservation Review (GCR) sites.
The Geological Conservation Review is produced by the UK's Joint Nature Conservation Committee. Their site list includes a number of locations within the SSSI. 
Nuttall and Hewitt mountains.
Management of the SSSI has to balance ecological and recreational demands. For example, the area contains a number of Nuttall and Hewitt mountains defined by the heights of their summits above the ordnance datum exceeding , and their topographic prominence (relative height). Three of them are also Marylins, with prominences exceeding , and Skiddaw is also a Furth, by exceeding in height.