Old Saint Hilary's Church was built in 1888 as a mission church serving the railroad workers and residents of the Tiburon Peninsula. The simple wooden building, with its Gothic-arched windows and modest steeple, sits on a hilltop that commands views across Richardson Bay to San Francisco. The church was decommissioned and fell into disrepair before being restored by the Belvedere-Tiburon Landmarks Society, which now maintains it as a historic landmark and community gathering space.

The grasslands surrounding the church support several plant species that are found nowhere else or in very few locations. The serpentine soil on the hillside creates conditions that most plants cannot tolerate but that a few specialized species have adapted to thrive in. The black jewel-flower, a member of the mustard family, is one of these serpentine endemics -- a plant whose entire natural range consists of this single hillside in Tiburon. The preserve protects these species from the development that has consumed most of the surrounding landscape.

The preserve connects to the 24-acre Tiburon Uplands, creating a contiguous area of protected open space on the Tiburon Peninsula. The trail system offers views across the bay that are among the best in Marin County. In spring, the grasslands bloom with wildflowers -- a display that draws botanists and casual visitors alike. The combination of a restored nineteenth-century church, globally rare plants, and panoramic bay views makes this small preserve one of the most distinctive parks in the Bay Area.