Pike County is a county located in the Appalachian region of the U.S. state of Ohio. According to the 2010 census, it has a population of 28,709, which is an increase of 3.7% from 27,695 in 2000. Its county seat is Waverly and 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.

According to the 2010 census, the county has a total area of 443.98 square miles (1,149.9 km²), of which 440.28 square miles (1,140.3 km²) (or 99.17%) is land and 3.69 square miles (9.6 km²) (or 0.83%) is water.

As of the census of 2000, there were 27,695 people, 10,444 households, and 7,665 families residing in the county. The population density was 63 people per square mile (24/km²). There were 11,602 housing units at an average density of 26 per square mile (10/km²). 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.

Ohio (ⁱ/oʊˈhaɪ.oʊ/) is a state in the Midwestern United States. Ohio is the 34th most extensive, the 7th most populous, and the 10th most densely populated of the 50 United States. The state's capital and largest city is Columbus.

The name "Ohio" originated from Iroquois word ohi-yo’, meaning "great river". The state, originally partitioned from the Northwest Territory, was admitted to the Union as the 17th state (and the first under the Northwest Ordinance) on March 1, 1803. Although there are conflicting narratives regarding the origin of the nickname, Ohio is historically known as the "Buckeye State" (relating to the Ohio buckeye tree) and Ohioans are also known as "Buckeyes".

The government of Ohio is composed of the executive branch, led by the Governor; the legislative branch, which comprises the Ohio General Assembly; and the judicial branch, which is led by the Supreme Court. Currently, Ohio occupies 18 seats in the United States House of Representatives. Ohio is known for its status as both a swing state and a bellwether in national elections.

Pike County is the name of ten counties in the United States:

All were named to honor Zebulon Pike.