Machen House is a country house in the hamlet of Lower Machen, to the west of the city of Newport, Wales. The house was built in 1831 for the Rev. Charles Augustus Morgan, vicar of Machen and scion of the Morgan family of Tredegar House. In the mid-20th century, Machen was the home of the Conservative politician Peter Thorneycroft, who sat as the Member of Parliament for Monmouth. Machen House is a Grade II* listed building. Its gardens and grounds are listed at Grade II on the Cadw/ICOMOS Register of Parks and Gardens of Special Historic Interest in Wales. A bothy and a bee bole in the grounds of the house are both listed at Grade II. The house remains a private residence and is not open to the public.