the Nepean flowed into the Hawkesbury. Nepean river was also one of the pivotal sites of the Hawkesbury and Nepean Wars, fought between the Kingdom of Great Britain and local aboriginal clans in the late 1700s and early 1800s. During the 1820s, the Nepean district's most famous early settler, the landowner and physician Sir John Jamison (1776–1844), erected a Georgian mansion, called Regentville House, on the model estate which he had established on a rise overlooking the river, not far from the present-day city of Penrith. Jamison is considered one of early Australia's most important political and agricultural pioneers. A fire devastated the house in the 1860s. Crossings Despite forming the effective western and south-western boundary of the metropolitan region of Sydney for its entire length, there are very few fixed crossings of the Nepean River. Going upstream, these comprise: Floods in the Nepean district The first flood on record - apparently a small occurrence - was in 1795. Others followed in 1799, March & October 1806 and 1809. In 1810, after a series of major floods on the Hawkesbury, Governor Macquarie proclaimed the ‘Macquarie Towns’ of Windsor, Richmond, Wilberforce, Castlereagh, and Pitt Town in an attempt to ensure that development was restricted to higher ground, free of flooding. The devastation caused by flooding in February, 1817 prompted Governor Macquarie to issue a notice exhorting settlers, in the strongest possible terms, to build their residences above the established flood levels. More flooding occurred in 1857 and twice in 1860, both February and May. The most devastating flood occurred in June 1867 with the Nepean River estimated to have reached in the river, and AHD. This flood carried away the approaches to the recently built Victoria Bridge. Emu Plains, Castlereagh, and the lower parts of Penrith were all under flood, causing immense loss of property. Many houses were carried into the river by landslides. Many residents were forced to take refuge in public buildings such as the Penrith Hospital and the public schools. A major flood such as that of 1867 would cause inundation of over 16,000 dwellings and damage costing approximately A$1.4 billion. There have been other notable floods since, particularly that of July 1900 and March 1914. Again there was much flooding of streets and loss of houses and property along the river. 1974 was another significant La Niña flood event. During the 2021 New South Wales floods, the