Pike County is a county located in the Appalachian (southern) region of the U.S. state of Ohio. As of the 2020 census, the population was 27,088. Its county seat is Waverly. The county is named for explorer Zebulon Pike.

Pike County was organized on February 1, 1815, from portions of Scioto, Ross, and Adams Counties, and was named in honor of Zebulon Pike, the explorer and soldier who had recently been killed in the War of 1812. Pike County was the site of the Pike County Massacre where eight members of the Rhoden family were shot and killed the evening of April 21–22, 2016.

According to the U.S. Census Bureau, the county has a total area of 444 square miles (1,150 km), of which 440 square miles (1,100 km) is land and 3.7 square miles (9.6 km) (0.8%) is water.

• Ross County (north)
• Jackson County (east)
• Scioto County (south)
• Adams County (southwest)
• Highland County (west)

Historical population

Census	Pop.	Note	%±
1820	4,253		—
1830	6,024		41.6%
1840	7,626		26.6%
1850	10,953		43.6%
1860	13,643		24.6%
1870	15,447		13.2%
1880	17,927		16.1%
1890	17,482		−2.5%
1900	18,172		3.9%
1910	15,723		−13.5%
1920	14,151		−10.0%
1930	13,876		−1.9%
1940	16,113		16.1%
1950	14,607		−9.3%
1960	19,380		32.7%
1970	19,114		−1.4%
1980	22,802		19.3%
1990	24,249		6.3%
2000	27,695		14.2%
2010	28,709		3.7%
2020	27,088		−5.6%
U.S. Decennial Census 1790-1960 1900-1990 1990-2000 2020

As of the census of 2000, there were 27,695 people, 10,444 households, and 7,665 families living in the county. The population density was 63 people per square mile (24 people/km). There were 11,602 housing units at an average density of 26 units per square mile (10/km). The racial makeup of the county was 96.72% White, 0.89% Black or African American, 0.74% Native American, 0.18% Asian, 0.04% Pacific Islander, 0.07% from other races, and 1.36% from two or more races. 0.56% of the population were Hispanic or Latino of any race.

There were 10,444 households, out of which 35.50% had children under the age of 18 living with them, 56.80% were married couples living together, 11.90% had a female householder with no husband present, and 26.60% were non-families. 22.80% of all households were made up of individuals, and 10.40% had someone living alone who was 65 years of age or older. The average household size was 2.61 and the average family size was 3.04.

In the county, the population was spread out, with 27.20% under the age of 18, 8.90% from 18 to 24, 28.90% from 25 to 44, 21.50% from 45 to 64, and 13.60% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 95.40 males. For every 100 females age 18 and over, there were 92.50 males.

The median income for a household in the county was $31,649, and the median income for a family was $35,934. Males had a median income of $32,379 versus $20,761 for females. The per capita income for the county was $16,093. About 15.10% of families and 18.60% of the population were below the poverty line, including 23.20% of those under age 18 and 13.60% of those age 65 or over.

As of the 2010 United States Census, there were 28,709 people, 11,012 households, and 7,743 families living in the county. The population density was 65.2 inhabitants per square mile (25.2/km). There were 12,481 housing units at an average density of 28.3 units per square mile (10.9 units/km). The racial makeup of the county was 96.6% white, 0.9% black or African American, 0.5% American Indian, 0.2% Asian, 0.2% from other races, and 1.6% from two or more races. Those of Hispanic or Latino origin made up 0.7% of the population. In terms of ancestry, 19.3% were German, 14.8% were Irish, 12.9% were English, and 12.5% were American.

Of the 11,012 households, 34.6% had children under the age of 18 living with them, 51.2% were married couples living together, 13.1% had a female householder with no husband present, 29.7% were non-families, and 25.1% of all households were made up of individuals. The average household size was 2.56 and the average family size was 3.02. The median age was 39.2 years.

The median income for a household in the county was $35,912 and the median income for a family was $43,010. Males had a median income of $40,645 versus $27,422 for females. The per capita income for the county was $17,494. About 18.0% of families and 23.6% of the population were below the poverty line, including 32.7% of those under age 18 and 15.2% of those age 65 or over.

The Garnet A. Wilson Public Library serves area communities from its main branch in Waverly, Ohio and from its branches in Beaver, Piketon, and Western Pike County.

In 2005, the library loaned more than 238,000 items to its 20,000 cardholders. Total holding are over 91,000 volumes with over 210 periodical subscriptions.

• 
  Waverly Library
• 
  Beaver Library
• 
  Piketon Library
• 
  Western Pike Library

Pike County has adopted a county flag with an unusual shape, rounded at the fly end. It bears fourteen stars, representing the county's townships, and various industry symbols within a circular emblem, all upon a green field. The flag is through and through except for the emblem.

Pike County used to be very strongly Democratic in presidential elections, being the only county in the state to vote for Adlai Stevenson in 1956. However, things have changed recently; Bill Clinton in 1996 was the last Democrat to win the county, though Barack Obama lost here by only one vote in 2012. In 2016, the county took a sharp turn to the right as Republican Donald Trump won over 65% of the vote in the county; he went on to win over 70% four years later.

United States presidential election results for Pike County, Ohio

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2020	9,157	73.70%	3,110	25.03%	157	1.26%
2016	7,902	66.12%	3,539	29.61%	510	4.27%
2012	5,685	49.03%	5,684	49.02%	227	1.96%
2008	6,162	49.27%	6,033	48.24%	311	2.49%
2004	6,520	51.84%	5,989	47.62%	67	0.53%
2000	5,333	50.50%	4,923	46.62%	304	2.88%
1996	3,759	34.85%	5,542	51.38%	1,486	13.78%
1992	4,094	35.93%	5,057	44.39%	2,242	19.68%
1988	5,611	51.39%	5,191	47.54%	117	1.07%
1984	6,318	55.90%	4,895	43.31%	89	0.79%
1980	4,426	45.08%	4,938	50.30%	454	4.62%
1976	3,729	38.95%	5,734	59.89%	111	1.16%
1972	5,037	57.49%	3,531	40.30%	193	2.20%
1968	3,247	40.01%	3,445	42.45%	1,423	17.54%
1964	2,567	32.50%	5,331	67.50%	0	0.00%
1960	3,684	45.92%	4,339	54.08%	0	0.00%
1956	3,447	47.15%	3,863	52.85%	0	0.00%
1952	2,982	43.37%	3,893	56.63%	0	0.00%
1948	2,639	36.85%	4,516	63.06%	6	0.08%
1944	3,117	43.99%	3,968	56.01%	0	0.00%
1940	3,165	38.94%	4,962	61.06%	0	0.00%
1936	2,953	35.82%	5,287	64.13%	4	0.05%
1932	2,743	34.69%	5,107	64.58%	58	0.73%
1928	3,246	54.51%	2,709	45.49%	0	0.00%
1924	2,569	43.87%	3,185	54.39%	102	1.74%
1920	3,075	52.08%	2,799	47.41%	30	0.51%
1916	1,616	43.06%	2,091	55.72%	46	1.23%
1912	1,184	34.45%	1,691	49.20%	562	16.35%
1908	1,798	45.54%	2,085	52.81%	65	1.65%
1904	1,818	45.69%	2,090	52.53%	71	1.78%
1900	2,342	53.98%	1,960	45.17%	37	0.85%
1896	2,228	50.64%	2,145	48.75%	27	0.61%
1892	1,686	44.47%	1,926	50.80%	179	4.72%
1888	1,769	43.90%	2,162	53.65%	99	2.46%
1884	1,792	43.78%	2,238	54.68%	63	1.54%
1880	1,756	44.16%	2,192	55.13%	28	0.70%
1876	1,465	41.14%	2,096	58.86%	0	0.00%
1872	1,284	45.01%	1,568	54.96%	1	0.04%
1868	1,155	40.08%	1,727	59.92%	0	0.00%
1864	1,048	41.24%	1,493	58.76%	0	0.00%
1860	958	38.44%	1,397	56.06%	137	5.50%
1856	523	25.23%	1,175	56.68%	375	18.09%

• Waverly (county seat)

• Beaver
• Piketon

• Cynthiana
• Stockdale

• Arkoe
• Buchanan
• Camp
• Daleyville
• Idaho
• Jasper
• Latham
• Morgantown
• Omega
• Sargents
• Wakefield

• National Register of Historic Places listings in Pike County, Ohio
• Pike County, Ohio, shootings

• Pike County Visitors Bureau website
• Pike County Sheriff's Office

39°05′N 83°04′W / 39.08°N 83.07°W / 39.08; -83.07