Orleans House was a Palladian villa originally built in the early 18th century near to the Thames at Twickenham, England, for the politician and diplomat James Johnston. It was subsequently named after the Duc D'Orleans who stayed there in the early 19th century. By the early 20th century it was derelict and in 1926 it was mostly demolished. However, parts of the property, including a baroque octagonal room designed by architect James Gibbs, were preserved and are now the Orleans House Gallery, a gallery of art relating to the London Borough of Richmond upon Thames and neighbouring areas of London.
More information on the Wikipedia page [1]. The Orleans House Gallery website is [2].