The Mersey Estuary is a tidal estuary located in northwest England, where the River Mersey meets the Irish Sea. It stretches approximately 70 kilometers and serves as an important waterway for shipping and trade. The estuary is surrounded by several towns and cities, including Liverpool and Birkenhead, which have historically relied on the river for economic activities. The estuary is also known for its diverse ecosystems, providing habitats for various wildlife species. It is part of the Mersey Estuary National Nature Reserve, which aims to protect the area's natural environment and promote biodiversity. The estuary plays a crucial role in both the local economy and ecology.