The Nepean River is a major river located in New South Wales, Australia. It flows approximately 250 kilometers, starting from the Blue Mountains and eventually joining the Hawkesbury River. The river is known for its scenic beauty and recreational activities, including fishing, kayaking, and walking trails along its banks. The Nepean River is an important water source for the surrounding communities and supports local ecosystems. It is also historically significant, as it was explored by Governor Lachlan Macquarie in the early 19th century. The river plays a vital role in the region's geography and culture.