HERMITAGE The Hermitage, a National Historic Landmark, is located on five acres of lawn shaded by centuries-old trees. The site is listed on the State and National Registers of Historic Places. The fourteen-room Gothic Revival home was built in 1847-48 from designs by William H. Ranlett for Elijah Rosencrantz Jr. house incorporates portions of a historic 18th-century house The Hermitage is owned by State of New Jersey operated by the Friends of the Hermitage, Inc Friends of the Hermitage, Inc, a private, nonprofit 501 ( c ) ( 3 ) corporation, was founded in 1972 to restore, maintain, interpret the site Hours: The Hermitage Museum ( historic house, exhibition galleries, and gift shop ) is open to the public Wednesday through Sunday, 1 p.m. - 4 p.m. We are closed to the public on Monday and Tuesday