Illawarra a monumental and elaborate two storey brick mansion with dominant tower is located on a most elevated site off St Georges Road,Toorak. it was erected in 1889-91 by builder G B Leith for prominent land speculator Charles Henry James. The uniquely detailed 'boom style' mansion, designed by James Birtwistle to replace an earlier residence on the same site, is constructed of high quality materials with excellent and opulent interior finishes.
Illawarra, historically significant as the residence of the infamous and unabashed land boomer politician C H James is a well known Toorak landmark and an outstanding work of comparatively unknown architect James Birtwistle. The ornate mansion epitomises the spectacular excesses of the final years of the land boom and is of architectural importance as a unique composition which prophetically foreshadows Edwardian innovations and trends of the early 20th century.
Illawarra is a building of outstanding craftsmanship standing on a restricted suburban site in Toorak. The mansion house is well preserved, essentially intact, currently occupied by St Catherine's School, under the guardianship of the National Trust.