1870s. The park has historical values at a state level for its ability to demonstrate the rise of harbour side recreational activity in 20th century. It was one of the first major recreational reserves created along the southern shore of Sydney Harbour, instigated by a large public push to secure foreshore land in public ownership. Shark Bay, bordered by the current swimming enclosure, together with structures including the kiosk, bathing pavilion and promenade demonstrates the growth in popularity and evolving trends in public bathing and recreational activities. The historical significance of Nielsen Park across its various phases of use is enhanced through association with a number of notable colonial figures, including William Wentworth, author, barrister, landowner, and statesman; the Reeve family who built the Greycliffe estate and, with noted mid-19th century architect and surveyor, John F. Hilly who designed Greycliffe and its outbuildings. It is also associated with William Notting, Secretary of the Harbour Foreshores Vigilance Committee and Park Trustee, who led the public move to have the area preserved and with Secretary of Lands at the time and Niels Nielsen who provided government support for the establishment of the park. The later use of Greycliffe as an Infant Hospital saw a close association with eminent paediatrician Dr Margaret Harper, whose work on infant diet, care and disease has remained highly influential. The site demonstrates multiple layers of significance including native bushland, rich Aboriginal sites, a substantially intact Victorian Marine Villa estate, 20th-century hospital complex and 20th-century public recreational space. Each phase of use has yet to be dominated by newer developments, and in combination allows the site to contribute to the landmark qualities of Nielsen Park as seen from within the park and from the waters of Sydney Harbour. Nielsen Park was listed on the New South Wales State Heritage Register on 28 August 2017 having satisfied the following criteria. The place is important in demonstrating the course, or pattern, of cultural or natural history in New South Wales. Nielsen Park Reserve may be of state heritage significance as it demonstrates the entire range of human occupation of the site including pre-colonisation. A variety of archaeological and art sites within the park demonstrate the place of this landscape in Birrabirragal Aboriginal country. Nielsen Park forms part of one of the first land grants in Australia. It forms part of the original grant to William Charles Wentworth, excised to form