Westerville is a city in Franklin and Delaware counties in the U.S. state of Ohio. A northeastern suburb of Columbus, its population was 39,190 at the 2020 census. The city is home to Otterbein University. It was once known as the "Dry Capital of the World" for its strict laws prohibiting sales of alcohol and for being the home of the Anti-Saloon League, one of the driving forces behind the Prohibition era at the beginning of the 20th century.