Gillette Castle State Park, Stone castle and state park in Lyme, United States.

Gillette Castle State Park is a state park with a stone castle in Lyme, Connecticut, covering 14,000 square feet and sitting on a bluff above the Connecticut River. The grounds include forested hiking paths and several overlooks with views of the river valley.

William Gillette built his residence between 1914 and 1919, with an addition finished in 1924, on a 184-acre tract atop the southernmost of the Seven Sisters hills. He died in 1937, and the State of Connecticut bought the property in 1943 for $29,000, renaming it Gillette Castle State Park. It joined the National Register of Historic Places in 1986.

The actor left personal design choices throughout the building, including wooden furniture built directly into the walls. Many of these installations feature moving parts and mechanisms that visitors can still try today.

The grounds remain open daily from 8 in the morning until sunset, while tours of the castle run from May through October. Visitors should bring sturdy footwear for the trails and the uneven stone floors inside.

The owner laid out a miniature railway system that wound for several miles through the estate woodlands. Guests could ride in small carriages through the forested grounds and reach different viewing points.