Osbornedale State Park is a 417-acre public recreation area along the Housatonic River in Derby and Ansonia that developed from the former Osborne family estate. Built from farms assembled by Frances Osborne Kellogg and Waldo Kellogg as Osbornedale Farms, the property supported Holstein breeding, Jersey dairy production, and earlier activities including post-Revolutionary War silver mining and spring water bottling. After Frances Osborne Kellogg left 350 acres to Connecticut at her death in 1956, the land became the core of the park. Today it blends historic sites, including the Osborne Homestead and Kellogg Environmental Center, with trails, fishing, ice-skating, and picnic areas.