The Wales Preserve is 4.5 miles south of Peterborough in Sharon on a plateau of rolling, wooded, hilly uplands averaging between 900 and 1,200 feet above sea level. Temple Mountain, at 2,005 feet, is four miles to the east, and Grand Monadnock, at 3,165 feet, is seven miles northwest.

The most prominent feature of the preserve is the Gridley River. Also known as McCoy's Sabbath Day Trout Creek, the tannin-stained stream has brook trout in its upstream reaches. A series of small cascades hasten the Gridley's descent. Along its course through the preserve lies a series of tiny islands, one of which supports the preserve's largest tree, a white pine measuring 34 inches in diameter, as well as a variety of wetland plant species. Approximately 700 feet in from the road, a power line cuts a fifteen-foot wide swath roughly north to south across the preserve. Much of this formerly cleared corridor is fast becoming overgrown with saplings and shrubs and provides excellent browse for the white-tailed deer and snowshoe hare. Beaver have been active in the area to the east of the preserve.

The Gridley River bank presents a lush appearance in midsummer: thriving stands of royal, sensitive, and cinnamon ferns crowd the bank, some even colonizing exposed midstream rocks. They vie for space with whorled wood asters and eastern Joe-pye weed. The islands and surrounding wetlands are dotted with common arrowhead, greater blue flag, tall rattlesnake root, Jack-in-the-pulpit, bloodroot, tall meadow rue, and dwarf enchanter's nightshade. Clintonia and trailing arbutus are abundant in the wet woods near the stream. Here, witch hazel, lowbush blueberry, witherod, and hobblebush predominate. Partridgeberry, wintergreen, starflower, painted trillium, pink lady's slipper, and bunchberry are but a few of the wild flowers which grow throughout the Wales Preserve.

The surrounding wooded slopes on the preserve grade from hemlock and red maple along the streambed to a mixed coniferous and de