Ohio Counties

Known species: 173
Observations: 222,670
Population: 11,570,808
Area in Square Miles: 40,847
People per Square Mile: 282
Observations per Square Mile: 5.5

Ohio iNaturalist observations

This column-sortable table provides the number of sightings and the number of species, along with demographic and geographical data, for Ohio’s 88 counties.

The county names link back to the respective county pages. Each county page provides a list of the odonata species that have been observed in that county, including columns on the number of observations, and most recent year each species was observed. Each county page provides a link to the county’s publicly viewable iNaturalist observations

Ohio Counties and Associated Odonata Observation Statistics

County	Species	Observations	Population	Square Miles of Land	People/Sq Mile	Obs/Sq Mile	% of State Species	% of State Observations
Adams	90	1,742	28,105	584	48	3.0	52%	0.8%
Allen	56	942	105,298	403	259	2.3	32%	0.4%
Ashland	97	1,795	53,043	423	124	4.2	56%	0.8%
Ashtabula	107	13,616	99,811	702	74	19.4	62%	6.1%
Athens	86	1,198	64,681	504	127	2.4	50%	0.5%
Auglaize	56	846	45,920	401	114	2.1	32%	0.4%
Belmont	53	897	69,571	532	128	1.7	31%	0.4%
Brown	56	983	44,264	490	90	2.0	32%	0.4%
Butler	80	3,930	371,272	467	790	8.4	46%	1.8%
Carroll	62	1,386	28,275	395	71	3.5	36%	0.6%
Champaign	92	10,013	39,455	429	92	23.4	53%	4.5%
Clark	80	4,255	136,167	397	339	10.7	46%	1.9%
Clermont	82	2,498	200,218	452	435	5.5	47%	1.1%
Clinton	71	1,023	41,945	409	102	2.5	41%	0.5%
Columbiana	79	839	105,893	532	198	1.6	46%	0.4%
Coshocton	92	5,558	36,760	564	65	9.9	53%	2.5%
Crawford	68	1,092	42,808	402	106	2.7	39%	0.5%
Cuyahoga	91	4,310	1,263,154	457	2,764	9.4	53%	1.9%
Darke	76	1,818	52,376	598	87	3.0	44%	0.8%
Defiance	86	974	38,532	411	93	2.4	50%	0.4%
Delaware	88	2,187	184,979	443	404	4.9	51%	1.0%
Erie	86	1,942	76,048	252	122	7.7	50%	0.9%
Fairfield	87	2,015	148,867	504	293	4.0	50%	0.9%
Fayette	59	1,238	28,800	406	71	3.0	34%	0.6%
Franklin	114	15,014	1,212,263	532	2,228	28.2	66%	6.7%
Fulton	66	865	42,488	405	104	2.1	38%	0.4%
Gallia	73	991	30,621	467	65	2.1	42%	0.4%
Geauga	112	5,605	93,972	400	230	14.0	65%	2.5%
Greene	94	5,991	163,204	414	392	14.5	54%	2.7%
Guernsey	61	850	39,636	522	75	1.6	35%	0.4%
Hamilton	89	4,724	804,520	406	1,949	11.6	51%	2.1%
Hancock	81	2,650	75,773	531	142	5.0	47%	1.2%
Hardin	55	846	31,641	470	67	1.8	32%	0.4%
Harrison	62	997	15,622	402	38	2.5	36%	0.4%
Henry	57	883	28,092	416	67	2.1	33%	0.4%
Highland	68	877	43,299	553	78	1.6	39%	0.4%
Hocking	91	1,485	28,665	421	68	3.5	53%	0.7%
Holmes	65	957	43,593	423	103	2.3	38%	0.4%
Huron	58	996	58,889	491	119	2.0	34%	0.4%
Jackson	70	1,177	32,783	420	78	2.8	40%	0.5%
Jefferson	65	856	67,964	408	166	2.1	38%	0.4%
Knox	75	1,245	60,810	525	115	2.4	43%	0.6%
Lake	113	6,209	229,857	227	239	27.3	65%	2.8%
Lawrence	61	1,018	61,917	453	136	2.2	35%	0.5%
Licking	98	3,198	168,375	683	245	4.7	57%	1.4%
Logan	94	2,486	45,481	458	97	5.4	54%	1.1%
Lorain	83	5,133	302,827	491	321	10.5	48%	2.3%
Lucas	111	11,548	436,393	341	775	33.9	64%	5.2%
Madison	69	2,285	43,277	466	93	4.9	40%	1.0%
Mahoning	71	976	233,869	412	550	2.4	41%	0.4%
Marion	56	1,050	65,905	404	163	2.6	32%	0.5%
Medina	87	2,983	174,915	421	414	7.1	50%	1.3%
Meigs	59	931	23,496	430	54	2.2	34%	0.4%
Mercer	57	828	40,784	462	86	1.8	33%	0.4%
Miami	89	2,477	103,439	407	253	6.1	51%	1.1%
Monroe	58	759	14,585	456	32	1.7	34%	0.3%
Montgomery	100	8,004	535,846	462	1,153	17.3	58%	3.6%
Morgan	69	952	14,904	416	35	2.3	40%	0.4%
Morrow	63	1,372	35,033	406	86	3.4	36%	0.6%
Muskingum	80	1,587	85,231	665	127	2.4	46%	0.7%
Noble	50	820	14,628	398	36	2.1	29%	0.4%
Ottawa	84	1,633	41,153	255	67	6.4	49%	0.7%
Paulding	93	1,295	19,254	416	46	3.1	54%	0.6%
Perry	70	968	35,997	408	87	2.4	40%	0.4%
Pickaway	76	1,771	56,304	501	111	3.5	44%	0.8%
Pike	82	1,008	28,367	440	64	2.3	47%	0.5%
Portage	111	3,470	163,862	487	325	7.1	64%	1.6%
Preble	60	1,095	41,732	424	98	2.6	35%	0.5%
Putnam	58	1,013	34,088	483	70	2.1	34%	0.5%
Richland	75	1,031	121,773	495	243	2.1	43%	0.5%
Ross	76	1,113	77,910	689	112	1.6	44%	0.5%
Sandusky	67	1,090	60,098	408	144	2.7	39%	0.5%
Scioto	75	1,007	78,153	610	127	1.7	43%	0.5%
Seneca	54	1,004	55,914	551	101	1.8	31%	0.5%
Shelby	72	1,244	49,192	408	120	3.1	42%	0.6%
Stark	99	8,220	375,432	575	647	14.3	57%	3.7%
Summit	111	9,956	541,824	413	1,290	24.1	64%	4.5%
Trumbull	91	1,590	206,442	618	325	2.6	53%	0.7%
Tuscarawas	74	1,022	92,672	568	162	1.8	43%	0.5%
Union	60	1,452	53,306	432	122	3.4	35%	0.7%
Van Wert	56	832	28,459	409	69	2.0	32%	0.4%
Vinton	78	1,466	13,276	412	32	3.6	45%	0.7%
Warren	80	2,195	219,169	401	539	5.5	46%	1.0%
Washington	76	1,980	61,310	632	96	3.1	44%	0.9%
Wayne	77	1,578	115,071	555	207	2.8	45%	0.7%
Williams	111	2,479	37,500	421	89	5.9	64%	1.1%
Wood	70	991	129,264	617	208	1.6	40%	0.4%
Wyandot	66	1,445	22,447	407	55	3.6	38%	0.6%

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, which create its recognizable 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. County populations and density vary significantly, ranging from Franklin County, with 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.

Daily Observations for the state of Ohio are skewed to the earlier part of the season, tapering off in late summer and into fall as the species diversity and oda population slowly declines.

Number of Species Identified in Each Ohio County

Updated 25 January 2024