Franklin County is located in the Till Plains ecoregion. It is the state’s second most populous county, the second most densely populated one. It is the home of Ohio’s capital city, Columbus, which at almost 226 square miles represents over 40% of the entire county. Only about 8% of the sprawling city of Columbus is park space (which is about half the national city median). However, the county does benefit from the Columbus & Franklin County Metro Parks, which has 28,500 acres of land, some of which is located in the surrounding 6 counties. The county also many retention basins and other artificial ponds, some of which are visited by over 30 species. the Olentangy River joins the Scioto River in central Columbus. Major creeks in the county include Big Darby Creek, Big Walnut Creek, and Alum Creek.

Places to visit

• Battelle Darby Creek Metro Park “features more than 7,000 acres of forest, prairies and wetlands. It stretches along 13 miles of the Big and Little Darby creeks, both State and National Scenic Rivers. Besides the areas surrounding the creeks, there are also over 1,600 acres of restored wetlands and prairies." 69 species have been identified in the park.

• 41 species have been identified in the 148 acre Whetstone Park, which includes an artificial pond, Scioto River access, and Adena Brook. Note that the pond was drained in 2024 to eliminate an invasive fish species and it has subsequently undergone a complete renovation that should be scheduled in 2026. The Whetstone Prairie is a 5.1 acre area converted into native Ohio prairie with vernal pools and woodland buffer that sometimes attracts river species.

• Ohio State’s Wilma H. Schiermeier Olentangy River Wetland Research Park is a 52 acre research institute partially open to the public. 21 odonate species have been observed.

• Sawmill Wetlands Education Area is a 17 acre complex of vernal pools, surrounded by development. Swamp Darners can be observed in May and early June.

• Olentangy River Water Trail Map and Guide covers the area from SR 161 to Broad Street, showing access points, all riverside parkland, and facilities.

County Observation Activity

This graph shows the total number of odonata observations for the county in blue, with the average for all Ohio counties in orange. The season is divided into 10 or 11 day segments by Month – basically early-month, mid-month, and late-month.