State Route 47 is a state highway running from the Indiana border at Union City to Waldo, about ten miles (16 km) south of Marion. In Bellefontaine, State Route 47 follows the path of different streets from Main Street and Sandusky Avenue to the intersection just north of Mary Rutan Hospital, about one-half mile north of the Main-Sandusky intersection. The westbound portion of State Route 47 goes down Main, while the eastbound portion goes north on Madriver Street during this stretch. Nobody really knows why the route was designated this way when none of the streets involved are one-way. It was State Route 68 until 1933, when U.S. Route 68 was commissioned. Since both roads run through a common county in Ohio (Logan), and also since there is a rule that there can be no Ohio State Routes with the same number as US highways within Ohio, the number was changed to 47.

Waldo is a village in Waldo Township, Marion County, Ohio, United States. The population was 326 at the 2020 census. Waldo is part of the River Valley Local School District.