Hellenge Hill is a promontory on the southwest side of the larger Bleadon Hill, a western outlier of the Mendip Hills, separated from the main part of the range by the valley of the Lox Yeo River, which provides a course for the M5. 54 acres are protected as a nature reserve, including two broad ridges and the slopes below, all covered by short, calcareous grasses and wildflowers, plus a shallow, wooded ravine in between.
Two particularly rare plants grow here, Somerset hair grass and honewort, though not the white rock-rose which in addition to the other two is found at Purn Hill, another nature reserve half a mile west. Other plant species of note on Hellenge Hill include autumn ladies tresses, green-winged orchid, wild thyme, yellow wort, common broomrape, common centaury, ladies bedstraw and carline thistle, while the adder is the most notable animal.
The treeless upper slopes allow good, uninterrupted views south, over the Somerset Levels towards the Bristol Channel. All the grasslands are grazed, however, by cattle and sheep, so the immediate surroundings are not so special. A walk around all areas is about one mile, on paths or cross-country. The West Mendip Way passes close to the northwest corner of the site, leading west to Purn Hill and east to the top of Bleadon Hill.
The nature reserve, also part of a site of special scientific interest, can be reached by short paths off Shiplate Road along the south edge, in the village of Bleadon, but the usual access is from the north, along Roman Road. Parking for two or three vehicles is available in front of the gate into the uppermost field, right opposite the entrance to Bleadon Hill golf course. The reserve here is identified only by a small sign; there is no map or information board.
From Roman Road, the main path heads southwest, downhill, across two fields separated by sparse hedgerows, and into a third, which seems one of the best for wildflowers; an approximately triangular enclosure, with trees and gorse bushes to the south and east. Another path descends the ravine on the east side and rises again to another good wildflower field (just to the south), from where a loop can be made, returning northwards to Roman Road.