Lake Erie is the shallowest of the Great Lakes, with an average depth of about 50 feet (15 meters).

Despite being the smallest by volume, Lake Erie is the most prone to temperature fluctuations and is often affected by pollution and algae blooms due to its shallowness. Its shallow depth allows sunlight to penetrate more deeply, promoting the growth of algae and affecting water quality. However, the lake remains an important resource for recreation, fishing, and transportation in the region.