Otisco Lake is approximately 5.4 miles (8.7 km) long and 0.75 miles (1.21 km) wide at its widest point.[6] The lake has an average depth of 33 feet (10 m) and reaches a maximum depth of 66 feet (20 m).[7][8] It has a surface area of 2,048 acres (8.29 km2) and can hold 21 billion US gallons (79,000,000 m3) of water.[7] The lake's outflow enters first Onondaga Lake via Nine Mile Creek and then Lake Ontario via the Seneca and Oswego rivers.