In 2023, The Nature Conservancy marked 50 years of working at the Sunny Valley Preserve. Donated by the late George D. Pratt Jr. of Bridgewater in a series of transfers from 1973 to 1979, Sunny Valley Farm was originally purchased by Pratt's father in 1934. Over the years, Pratt went on to protect more than a dozen separate pieces of open or wooded lands in the area from developers before donating them to TNC to be protected while supporting sustainable farming and education.

Today, TNC's Sunny Valley Preserve boasts a variety of topography, geology and natural habitats along both sides of the Housatonic River Valley, including large stands of hemlock and mixed second growth hardwood forest that supports diverse wildlife and biological communities. Throughout its 1,850 acres of farmland, forests, wetlands and meadows – spread out across 19 parcels of land – visitors can hike on trails and learn about nature, land management and environmentally compatible farming at several observation sites.

Since assuming ownership, TNC has initiated surveys to develop an inventory of the preserve's wildlife and plants. TNC also created habitat to support New England cottontails, which were formerly listed as a federally threatened species but are in recovery thanks to this type of conservation effort.