Kilkenny Nature Reserve is a relatively small (13 acre) expanse of unimproved calcareous grassland, near the centre of the Cotswold Hills, five miles southeast of Cheltenham. The terrain is gently sloping, from south down to north, crossed by a few paths and dotted with low mounds, probably overgrown spoil heaps from ancient quarries, and the land is covered by a mix of long and short grass, plus bushes and occasional trees, and many wildflowers. There are no particularly rare plants here, but many of the characteristic species of limestone soils are abundant. Orchids include pyramidal, common spotted and broad-leaved helleborine, while two creatures of note are the adder and the Duke of Burgundy butterfly. This site is not grazed during the wildflower season.
The reserve is situated along the A436 a few hundred feet west of the Old Gloucester Road junction, beside which is the Kilkeney Inn. Unlike most nature reserves in the county, Kilkenny is served by a dedicated parking area accommodating several dozen vehicles, since it receives a comparatively large number of visitors, partly as the site is also a recognised picnic spot, and also because it includes a good, elevated viewpoint, at the high point of the grassland along the southern edge.
The driveway into the reserve branches east off a lesser road, on the south side of the highway. From the parking place, one short path leads to a more overgrown area in the northeast corner, a former quarry site, while another heads south into the main area of the short grassland. Across the reserve are patches of thicker, less calcium-rich soils where more common plants grow, but most has only the thin limestone soil, and here are found a greater variety including yellow wort, common centaury, bird's-foot trefoil, fairy flax, common restharrow, carline thistle, St John's wort and autumn gentian. The plants are broadly similar over the whole area, perhaps just a little less abundant across the higher reaches. The southwest corner of the site is occupied by a communications tower, and the best overall views are from the base.