Elizabeth Bay House is a heritage-listed Colonial Regency style house and now a museum and grotto, located at 7 Onslow Avenue in the inner eastern Sydney suburb of Elizabeth Bay in the City of Sydney local government area of New South Wales, Australia. The design of the house is attributed to John Verge and John Bibb and was built from 1835 to 1839 by James Hume. The grotto and retaining walls were designed by Verge and the carriage drive on Onslow Avenue was designed by Edward Deas Thomson and built from 1832 to 1835 by convict and free artisans under the direction of Verge. The property is owned by Sydney Living Museums, an agency of the Government of New South Wales. Known as "the finest house in the colony", Elizabeth Bay House was originally surrounded by a 22-hectare (54-acre) garden