Pemulwuy is named after the Aboriginal warrior, Pemulwuy, who led attacks on the British settlements in the surrounding areas, particularly on the Toongabbie settlement. When Captain-Lieutenant Watkin Tench made another official journey to the west in 1789, he began his journey with reference to Prospect Hill, which commanded a view of the great chain of mountains to the west. The first recorded ascent of Prospect Hill by a colonist is that of Tench and his party on 26 June 1789.