Osbornedale State Park is a public recreation area occupying 417 acres (169 ha) on the east bank of the Housatonic River primarily in the town of Derby, Connecticut, with a small portion in Ansonia.

The state park includes the historic Osborne Homestead, the Kellogg Environmental Center, and an extensive system of hiking trails.

[3] The park was formerly the estate of the Osborne family, the owners of metalworking and textile product factories in the Naugatuck Valley area.

Prior uses of the park land included silver mining in the years after the American Revolutionary War and bottling of spring water.

[3][4] The park preserves the historic Osbornedale house, which offers tours,[5] as well as an adjacent property that is part of the state's resident curator program.