The Filoli Nature Preserve occupies most of the acreage beyond the House, Garden, orchard and parking area. It is an outstanding area for nature education, offering a variety of ecosystems within a compact area including mixed forests, redwood stands, chaparral, riparian, pond and cultivated grasslands.
The preserve also contains historic Filoli sites such as the Bourn family cemetery, the Italian bachelor gardener dormitory (not open to the public), and old barns including one that has been converted to a classroom.
Wildflowers typically are in bloom from February through early summer. While many of the animals are nocturnal or elusive, deer, banana slugs and lizards are regularly seen on hikes. Many of the birds and mammals found at Filoli are displayed at the Sally Mac Bride Nature Center.
A portion of the preserve is accessible only through docent-lead nature hikes on a network of trails and historic roads. The Estate Trail and Sally MacBride Nature Center are open to self-guided hikes.