The Ohio Country (sometimes called the Ohio Territory or Ohio Valley by the French) was the name used in the 18th century for the regions of North America west of the Appalachian Mountains and in the region of the upper Ohio River south of Lake Erie. One of the first frontier regions of the United States, the area encompassed roughly the present-day states of Ohio, eastern Indiana, Western Pennsylvania, and northwestern West Virginia. The issue of settlement in the region is considered by historians to have been a primary cause of the French and Indian War and a contributing factor to the American Revolutionary War.

In the 17th century, the area north of the Ohio River had been occupied by the Algonquian-speaking Shawnees. Around 1660, during a conflict known as the Beaver Wars, the Iroquois seized control of the Ohio Country, driving out the Shawnee and conquering and absorbing the Erie tribe. The Ohio Country remained largely uninhabited for decades, and was used primarily for hunting by the Iroquois.

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.