Ohio Species

Number of species: 173

Cumulative Observations: 222,670

Ohio iNaturalist observations

This column-sortable table provides the cumulative sightings, and the number of sightings last year, for all the odonate species that have been observed in Ohio’s 88 counties.

Located on the St Lawrence Continental Divide between the Great Lakes Basin and the Mississippi River watershed, Ohio is a relatively small regional jurisdiction of 44,825 square miles (116,096 km2). It is bordered on the north by Lake Erie, and on the south by the Ohio River. These bodies of water influence the climate in the adjoining areas, and they create Ohio’s distinctive heart shape. The greatest distance between any two points in the state of Ohio is only 245 miles. For such a small and compact area, it has a diverse geophysical makeup, with five distinct ecoregions stretching diagonally across the state. These regions have a significant impact on the human history, and the natural history of our state, both of which influence the current distribution of odonate species. See the map Physiographic Regions of Ohio for details on Ohio's ecoregions.

Ohio has a population of just under 12 million people, giving it an overall population density of 282 people per square mile (109/km2). Its 88 counties vary significantly, ranging from Franklin County, which encompasses the state capital, Columbus, and has a population density of 2,203.4 people per square mile, to Monroe County on the state’s eastern border, which only has 31.9 people per square mile.

Updated 3 January 2025