Marietta is a city located in Washington County, Ohio, in the United States. It serves as the county seat and is situated in southeastern Ohio at the confluence of the Muskingum and Ohio Rivers. The city is positioned approximately 11 miles northeast of Parkersburg, West Virginia.
As of the 2020 census, Marietta has a population of 13,385 people. It functions as the principal city of the Marietta micropolitan area, which encompasses all of Washington County. Additionally, it is recognized as the second-largest city within the Parkersburg–Marietta–Vienna combined statistical area.