What lake borders the northern side of Ohio?

Lake Erie borders the northern side of Ohio. It is one of the five Great Lakes of North America and is positioned between the states of Ohio, Pennsylvania, and New York, as well as the Canadian province of Ontario. Ohio has a significant shoreline along Lake Erie, which plays a crucial role in the state's economy and recreation. This includes activities such as fishing, boating, and tourism, making it an important natural resource for Ohioans.

In contrast, the other bodies of water mentioned—Lake Michigan, Lake Huron, and Lake Ontario—do not share a border with Ohio. Lake Michigan is located to the northwest of Ohio, while Lake Huron and Lake Ontario are farther north and northeast, respectively, and are separated from Ohio by the other states and lakes in the region. Therefore, Lake Erie is the only correct answer in this context.