Cincinnati (pronounced /sɪnsɨˈnæti/) is a city in the U.S. state of Ohio. Cincinnati is the county seat of Hamilton County. Settled in 1788, the city is located north of the Ohio River at the Ohio-Kentucky border, near Indiana. The population within city limits is 296,943 according to the 2010 census, making it Ohio's third-largest city. According to the 2010 Census Bureau estimate, the Cincinnati metropolitan area had a population of 2,130,151, the 27th most populous Metropolitan Statistical Area (MSA) in the United States. Residents of Cincinnati are called Cincinnatians.

In the early 19th century, Cincinnati was the first American boomtown in the heart of the country to rival the larger coastal cities in size and wealth. As the first major inland city in the country, it is sometimes thought of as the first purely American city. It developed initially without as much recent European immigration or influence as took place in eastern cities. However, by the end of the 19th century, with the shift from steamboats to railroads, Cincinnati's growth had slowed considerably and the city became surpassed in population by many other inland Midwest cities, especially Chicago.

Cincinnati is home to two major sports teams, the Cincinnati Reds and the Cincinnati Bengals, a major tennis tournament, the Cincinnati Masters, and home to large events such as the Flying Pig Marathon, the Ohio Valley Jazz Festival, and the Thanksgiving Day race. The University of Cincinnati traces its foundation to the Medical College of Ohio, which was founded in 1819.