The Vermilion River is a river in northern Ohio in the United States. It is 59 mi (95 km) long and is a tributary of Lake Erie, draining an area of 268 mi² (694 km²). The name alludes to the reddish clay that is the predominant local soil along its route. The river is commonly muddy after rains.
A pleasure boat harbor is located along the river near its mouth at Lake Erie.
A short distance before the river enters Lake Erie, near State Route 2, it passes through a deep gorge. The Vermilion rest area along the northern (westbound) side of Route 2 features a short nature trail leading to an overview of the gorge.
Three short tributaries are known as branches or forks of the Vermilion River. The Southwest Branch Vermilion River and the East Branch Vermilion River join the Vermilion in Huron County. The East Fork Vermilion River rises in Lorain County and joins the Vermilion in Erie County.