Oak Harbor has a colorful history originating with a man named Adolphus Kraemer, a Toledo merchant who dreamed of developing a town that would rival the likes of Detroit and Cleveland. Adolphus established his dream town near the headwaters of the Portage River, 11 miles inland from Lake Erie. Although it was first platted in 1835 as Hartford by Joseph Wardlow, it was Kraemer who brought his family to settle in the wilderness and develop the town that became Oak Harbor. Since there were several Hartfords in Ohio, Kraemer suggested the name Oak Harbor because the village was located on a river harbor and there was an abundance of oak trees. Initially, Oak Harbor was a lumbering town, but as the timber began to wane, the area saw an influx of German immigrants who understood how to drain and farm the swampy land.
