Saint Johns is a census-designated place located along the border between the Union and Clay townships of Auglaize County, Ohio, United States. As of the 2010 census it had a population of 304.It is located between Indian Lake and Wapakoneta at the intersection of U.S. Route 33 and State Route 65. Served by the Wapakoneta City School District, the zip code for Saint Johns is 45884.