The Parramatta River is a key waterway in Sydney, Australia, flowing into Sydney Harbour. It was formed millions of years ago and has significant cultural importance to Aboriginal peoples. The river runs through Parramatta CBD, with weirs controlling its flow. There are ferry services along the river, and various bridges provide important crossings. Efforts are underway to improve water quality and make the river swimmable by 2025. Overall, the Parramatta River plays a vital role in the city's landscape and history.