Ohio is a Midwestern state of the United States. The thirty-fourth largest state by area in the U.S., it is the seventh-most populous with nearly 11.5 million residents. Ohio, whose name was derived from the Seneca word ohi:yo’, meaning "large creek,"] was formed primarily from the Ohio Territory and was admitted to the Union as the seventeenth state (and the first under the Northwest Ordinance) on March 1, 1803. Ohio is known as the "Buckeye State" for its prevalence of Ohio Buckeye trees, and, as such, Ohioans are also known as "Buckeyes."