Largest Reservoirs in Ohio

Ohio has 1370 dams with recorded storage capacity. The largest is Englewood Dam with 413,000 acre-feet of maximum storage. One acre-foot equals about 326,000 gallons — enough to supply roughly two households for a year.

#	Dam	County	Max Storage (acre-ft)	Height (ft)	Purpose	Year
1	Englewood Dam	Montgomery	413,000	121	Flood Risk Reduction	1922
2	Taylorsville Dam	Montgomery	386,000	78	Flood Risk Reduction	1922
3	Huffman Dam	Greene	297,000	73	Flood Risk Reduction	1922
4	William H. Harsha Dam	Clermont	294,800	205	Flood Risk Reduction	1973
5	Mohawk Dam	Coshocton	285,000	111	Flood Risk Reduction	1937
6	Caesar Creek Dam - Saddle Dike 2	Warren	242,200	180	Flood Risk Reduction	1976
7	Dover Dam - Fairfield Levee	Tuscarawas	210,600	30	Flood Risk Reduction	1937
8	Wills Creek Dam	Coshocton	196,000	87	Flood Risk Reduction	1936
9	Mosquito Creek Dam	Trumbull	180,000	47	Flood Risk Reduction	1944
10	Lockington Dam	Shelby	165,000	78	Flood Risk Reduction	1922
11	Grand Lake St. Marys - West Embankment	Mercer	156,383	20	Recreation	1841
12	Dillon Dam - Nashport Dike	Muskingum	154,000	48	Flood Risk Reduction	1959
13	Salt Fork Lake Dam	Guernsey	152,900	61	Recreation	1968
14	Hoover Dam	Franklin	145,079	86	Water Supply	1956
15	Germantown Dam	Montgomery	142,000	107	Flood Risk Reduction	1922
16	Berlin Dam	Mahoning	140,000	96	Flood Risk Reduction	1943
17	Alum Creek Dam	Delaware	134,800	93	Flood Risk Reduction	1974
18	Paint Creek Dam - Dike	Highland	128,390	70		1973
19	Michael J. Kirwan Dam	Portage	124,000	83	Flood Risk Reduction	1966
20	Bolivar Dam - East Sparta Levee	Stark	123,446	25	Flood Risk Reduction	1938
21	Senecaville Dam	Guernsey	88,500	45	Flood Risk Reduction	1937
22	Charles Mill Dam	Ashland	88,000	52	Flood Risk Reduction	1936
23	Rocky Fork Lake Dam	Highland	87,050	74	Recreation	1952
24	Beach City Dam - Silica Sand Levee	Tuscarawas	80,650	21	Flood Risk Reduction	1937
25	Piedmont Dam	Harrison	66,700	56	Flood Risk Reduction	1937
26	Clarence J. Brown Dam	Clark	63,700	98	Flood Risk Reduction	1973
27	Mineral Ridge Dam	Trumbull	62,000	60	Water Supply	1932
28	Tappan Dam	Harrison	61,600	52	Flood Risk Reduction	1936
29	Clendening Dam	Harrison	54,000	64	Flood Risk Reduction	1936
30	Atwood Dam	Tuscarawas	49,700	65	Flood Risk Reduction	1936
31	Lake Milton Dam	Mahoning	46,605	53	Recreation	1916
32	Bridge Creek Dam	Geauga	41,505	40	Water Supply	1961
33	Leesville Dam	Carroll	37,400	74	Flood Risk Reduction	1937
34	O'shaughnessy	Delaware	33,000	79	Water Supply	1924
35	John R. Doutt Upground Reservoir	Delaware	32,028	46	Water Supply	2014
36	The Ohio Valley Coal Slurry Disposal Dam	Belmont	30,746	275	Tailings	1981
37	Indian Lake Dam	Logan	30,322	16	Recreation	1852
38	Tom Jenkins Dam	Athens	26,900	84	Flood Risk Reduction	1950
39	Clear Fork Reservoir Dam	Richland	26,532	44	Water Supply	1949
40	Cowan Lake Dam	Clinton	24,974	63	Recreation	1947
41	Apple Valley Lake Dam	Knox	22,485	91	Recreation	1971
42	Mogadore Reservoir Dam	Portage	21,000	36	Recreation	1938
43	Acton Lake Dam	Butler	20,297	62	Recreation	1956
44	Buckeye Lake Dam	Licking	20,000	15	Recreation	1832
45	Findlay Upground Reservoir No. 2	Hancock	19,478	32	Water Supply	1971
46	Knox Lake Dam	Knox	18,980	52	Recreation	1954
47	Williams Reservoir	Allen	18,682	53	Water Supply	2012
48	Lake Rockwell Dam	Portage	18,250	35	Water Supply	1913
49	Bresler Upground Reservoir	Allen	18,140	38	Water Supply	1970
50	Nimisila Reservoir Dam	Summit	17,500	44	Water Supply	1936

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