The **Ohio River** forms Ohio's **entire southern and eastern border** (451 miles / 726 km). **All of Ohio lies north of the Ohio River**—it's the state's southern boundary. Therefore, **every major Ohio city is north of the Ohio River**.
However, if the question means **large cities in the *northern part* of Ohio** (near Lake Erie), the three largest are:
Other large northern Ohio cities: **Lorain, Elyria, Parma, Canton, Youngstown, Mansfield, Sandusky, Fremont, Port Clinton.**
Clarification: **Cincinnati, Portsmouth, Marietta, Steubenville** are **on the Ohio River** (north bank). **No Ohio city is south of it**—that's Kentucky/West Virginia.