Pihla, the largest peatland in Hiiu County, is located 6 km southwest of the city Kärdla, 4 km southeast of Lauka village, in the central part of the island. The peat formed by terrestrialisation of the remnant lake, feeds on groundwater and precipitation, the water recipient is Pihlaoja. Peat lies on sand and clay. Wooded bog, wooded mire and fen woodland spread in the peatland. The area of ​​the peatland is 3043 ha, of which 1863.02 ha is peat deposit; registry card no. 120. There is 0.070 million tons of slightly decomposed peat ( economic proved reserves) and 0.206 million tons economic probable reserves,  potentially economic reserves are  0.583 million tons.  Well-decomposed peat economic proved  reserves  are 0.459 million tons and economic probable reserve 1.36 million tons. There is 2.678 million tons of potentially economic reserves. The Pihla peat production area belonging to AS Hiiu Turvas, with an area of ​​200.93 ha,  where there is 0.069 million tons of slightly decomposed peat and 0.458 million tons  of well-decomposed peat. There are 2302 ha of fen peat deposit, 114 ha of mixed- bog deposit and 627 ha of bog deposit. The eutrophic peat layers are located in the northern and eastern part of the bog and elsewhere in the periphery, consisting of well-decomposed (42%) sedge, reed and wood  peat. The thickness of the deposit is 1.50-2.00 m, ash content is 5.4% and moisture content is 91%. The upper layers  are slightly decomposed (13%)  peat, thickness 0.80 ... 0.90 m, ash content is 2.3%. Sphagnum peat is found in the first layer.  The thickness of peat deposit is 2.70 ... 3.20 m, ash content is 4.2% , moisture content is 92%, decomposition is 39%. After cut away the slightly decomposed peat layer, it is expedient to continue the production of well-decomposed peat. Extending peat production fields  to the natural areas is not recommended, as it would disturb the whole island's groundwater regime. Well- decomposed peat could be a raw material for humic substances (Orru et al., 1988). Based on the list of usable peat areas prepared by the Ministry of the Environment, it is permitted to extract peat on 443.8 ha (Regulation no. 87.12.2016).