Cincinnati is a city in southwestern Ohio, in the United States of America, that lies on the Ohio River. It is the county seat of Hamilton County. As of 2005, Cincinnati's population was 331,310, making it the third largest city in Ohio and the 56th largest in the United States. It has a much larger metropolitan area, commonly called "Greater Cincinnati", which covers parts of Ohio, Kentucky, and Indiana. As of July 1, 2005, the U.S. Census Bureau esimates that the Cincinnati-Middletown-Wilmington Combined Statistical Area has a population of 2,113,011 (making it the 20th largest in the country) and is growing at a rate of about one percent annually.

According to the United States Census Bureau, the city has a total area of 206.1 km² (79.6 mi²). 201.9 km² (78.0 mi²) of it is land and 4.1 km² (1.6 mi²) of it (2.01%) is water. The Cincinnati-Middletown-Wilmington Combined Statistical Area has a population of 2,113,011 people and is the 20th largest in the country. It includes the Ohio counties of Hamilton, Butler, Warren, Clermont, and Brown, as well as the Kentucky counties of Boone, Bracken, Campbell, Gallatin, Grant, Kenton, and Pendleton, and the Indiana counties of Dearborn, Franklin, and Ohio.