The Fox Mansion, perched on a promontory of land at the confluence of the Allegheny and Clarion rivers, is a nearly square, stone building with a pyramidal roof and a two-story wing to the north. It was built in stages between 1827 and the late 1870s, when stone cladding was added to unify the whole. The Foxes, a Quaker family from Philadelphia, had owned the land since 1796 and used it as a summer residence. The last Fox owner sold the property in 1966, and it underwent two attempts at development before it was acquired by its current owner.

Architect Lee Ligo of Slippery Rock was commissioned in the late 1990s to complete the rehabilitation of the house and grounds. He added a cupola to the roof and designed a larger version of the cupola as a porte-cochere on the east elevation. Both have small peaked dormers that echo those on the carriage house to the east designed by Frank Furness (
CL25). South of the carriage house is the greenhouse, which was rebuilt, as was more than a mile of low-lying stone walls delineating gardens and sections of the estate cleared for barns. A quadrangle of barns east of the carriage house was built, reusing older pin-connected timber frames moved to the site and clad with new cedar siding. A group of late-twentieth-century buildings southeast of the barns consists of two houses and a large carriage house–garage. They were modified by Ligo from the designs of Hearth Stone Log Houses of Tennessee.

The entire complex is rare in this part of Pennsylvania for its completeness, extravagant scale, and sophisticated design. The farm complex north of the mansion is distinguished by a set of four large gambrel-roofed barns, the western two originally built c. 1910 as dairy barns. The eastern two, built c. 2000 using wooden trusses and metal siding, contain a riding arena with a 100-foot clear span.